I run a Perspectives Notary Server. It is free for anyone to use.

What is Perspectives? -- Perspectives is a browser extension that verifies if other servers on the Internet are seeing the same SSL certificate you are being presented with when visiting a site using HTTPS.

Extensions available: Perspectives (Firefox)

To add these to your configuration in Firefox, left click on the blue "P" and click "Preferences". Then click "Notary Servers" in the tab section, then copy and paste the lines from below into the "Additional Notary Servers" box and when done click "OK".

My Notary Server

You can use it by adding this to your configuration:
notary.yano.me
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAHH17C/zqdzBW3y8Rov0UVFkme6
Idfd1O7wXckTdbd+bu7rClAFMbGijMlxYmNeavhJfyYmYct89dNlIyrnK9fa5PeL
q1g3zj5XybWi+UYrnwjcsKzCsZrWmqjx4ewICzCRypqj76k73eWwTxJ0F3ZWm/Va
VVe6slBxa/Vz6G/A5lgUUWYnktG9BnwnU1CCbQVE9vKnI/Kfv/mfBXbhkc0knRbR
JpMo07AyY2ECAwEAAQ==
-----END PUBLIC KEY-----

Other Notary Servers

Here are a few other Notary servers I have found across the Internet.
The first two listesd are run by Nicole Kohler. Source
heimdal.herokuapp.com:80
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAGhzbwVcnEaT2Hb9WD9Wvh9CVYu
86w+8ZMdO4KG506K77IsERfIuh84YkE4qoDnjfR7TCQBvreVl81lIh5UE0kzO84X
673risoBebbGCNjXQNu5mWkq2Qp7SuuemeXaYFmkpc06t2n6NvNcS9JVm8KJRqBK
qlwqlFgDuDZPUcYmWoIL4sF9w/3ep9nPSIJYburTdpCaeXPGhMiMzh4E2GnJc3Y2
beezGWtciXUCAwEAAQ==
-----END PUBLIC KEY-----
nine-eyes.herokuapp.com:80
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAEw+W1dv0a00gzVqvHa8SafHhpY
ESsCIB8kj4bb1ccXr7u6vaiBN83ssaPi1N/ZNDlyOnqZwopoZGkgzUxMUNzg9P6V
ph9l7ldMu8XGuwmFoHBgEys633EPcrJcs46lfvNz5JRrYnjh0WMkj0VXvVlYla2g
6aAA80+C7u56D2FodNxWscPNpQWUAHDJOnAWr1CI9CNU/rbl5c85KJ7cW6u+LFBm
pXk2xzJ2tq8CAwEAAQ==
-----END PUBLIC KEY-----
Quantum Anti-Bogom Sort (QABS) Source
notary2.qabs.cz:8080
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAGYNrXeOuExUPjrwisreOZ67ZTT
xaPVLncYrVrvE2Q3KzAqVvGlhyxZMnSLlHlHD5BJsA3bM/15ForpH/dJL+GnONZY
sQdgVdDXH30231bImuOzqBNCqMsTB4hxg9U6a1J4h7sa1eOn5Zz1EbDGuW2+jEcE
0MjqpaYEEW7FZiZOIJQRz4jX26zfGGhtd7txfkZQ26lhiibo9auCxp1tnVJmBX2S
VisNlAuuLM8CAwEAAQ==
-----END PUBLIC KEY-----
Christopher Schulte's Servers, Source
perspectives1.schulte.org:8080
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAF9YhEaUx+MR/9dw/ceF5+DAmTm
KRylGYKz+rfLSKMS1PMfkGiXVB12qkGOj321PrphLs2s9KWLcxHnCwJdQWcg2xIA
VQbZ2I5me2PEJNC+1Y9nqPR6AeKEljDPK/A1KiTjwDGjpvru8Djp25q++VJjhUZG
y0Wq845LMMUbQGefh05IL4Y9vuMWRUjs0C6enkI5CnCcMIFD1uY5+rsqknw1Nthn
2ZhTVfcjxTsCAwEAAQ==
-----END PUBLIC KEY-----
perspectives2.schulte.org:8080
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAGcQwe1IeEnF/ZobSywrpzbv6Uw
sZyxU7WThAaJ1EKy7UIYSrcJ6v/qurFwn9DwR8hxpXCgE8MRZdfVi99z69VE0Nmw
6vHLuC0PKQ/m3Gc+4LzfEyJ/fsPFsTsSqwog+ys8ehvCifoazewyLAZvVfBW3TVZ
uv7REooR5rWVrkI05z/VLpY9eSanWxaBJikHE3AnfOocI60ZIvq2eftIkpqCppwr
AZtwGtmxHa0CAwEAAQ==
-----END PUBLIC KEY-----
perspectives3.schulte.org:8080
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAG0L5/mnLvIjQbD6yazszjVBWCb
K7iUiav/M/9qoph2s1Nd2HSbEa2pZsNTtRrPNd2uPkYPGjkuhv5Ba3AMezN4eeEJ
pxa0wBSuYX7deUcQCu+0W/tLXZ61ny/Ezu/mnAQ10HIiO7mQnDTliF4ReSWC9TuR
axLr1tEh3i/pRoSOCtcWIR5y59BYu+GiPHl9IDOBraTG0R9ph+3fDVtf+kd+WUVv
/d0tWI0UmGsCAwEAAQ==
-----END PUBLIC KEY-----
perspectives4.schulte.org:8080
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAF+1OV01dpujDpFoUtld37Pgy4/
67E7EFB7YyHkfQbTuPnfZ2+UNScl80vcmN1hym8XJ0icPahah+SXMLq81UNxO6Xq
4s/41C5IxjnZN2Ij3EvhSPQ9HrK9+CVUmLWTWQRG7t5JaKGdlmYc5Fou1/SMoURZ
z4LWWGwcYH5/DcBt64XL5c87v4g3mfCDptmFMg5Cy34uG+XEh0obvp5S+uuORwn1
agGH5DYpR1sCAwEAAQ==
-----END PUBLIC KEY-----

notary.cm.my1.cc
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAHjw7lOgJw26HD31+FuGbZTUOQT
+GEwSiU25xe5SWaPzRciRir7EhVd8SaYuhkqDyyRuIeWNV6FP/LdpH45LRQRATZx
O+9Z9DD/D8XydIGpobCsK9Rd4dByqU3/DVUAGyO6tietTab7iPRynp+yN8TEjdrp
xLAcDPaujPv/ZrlZvE+P1Z3ZumUFz7/N9KYMXnK+uIa8xdwadyZYs+rG40Amtf1m
ppW4dIJAHyUCAwEAAQ==
-----END PUBLIC KEY-----
notary1.chaz6.com:8080
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAF7BPUua7HJclE1XQ/DynM+2/1t
I3oZS4+SliIu2KA7PUBNzjhVI4FmKgTVR+1gqGbuF/NNspOUbUH9B5SftsSQYt3e
1O/qY5H5kKytr2xTIHUp8QoAzaeWG5EcvZL8i4nwdwvBtcIlLJTKPDvy9Yy0Fg9K
84T8ewHKTfl44nbqUknX+SDn8BLutxZwbVV3uitUS8hVAT6zxw+yYc4WCpVJxO+h
3KEmMMVnu8MCAwEAAQ==
-----END PUBLIC KEY-----
notary.stupidpupil.co.uk
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAFGQ7aCe70wrc/VrFsxaVzrf0Jn
UDdVG+xz11VL34bodkxaPgazHKn3xNABB+1M/nvCLh/SwsiAQvKoIiFvPPhnuDLb
xXaDJEd/EJLEbyfB7OIwDNPlQBNkH8mHZO/RrVU2VOKvdK9KC3LCYTixzuoUjWp7
CzukQix1VlwJheTV2yo66notSVP/9xRFq0MOrsOljUlORYFpnYv7DTNDUvthVTCO
CMpPu3EIcM0CAwEAAQ==
-----END PUBLIC KEY-----
perspectives01.exodica.com.ar
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAG2NH8WCyg4mnYTQ9M3Aef5cHR7
IE/8ADHzdnQcMteZtdeecpIwAhOoP64RdSs5T09GIDG2eD7Fd9MABe+tLGO/VMUp
bb4FSKkjhn6U5CX8kYXlytTmHUc9LGcUCJKUY0ghO4cpW1mFli3p+ve96SKrxtze
un5TLQT3qJB5tdnSzdrNTi9PSeIzfKmGmdegknUgblohQktzGi6Wc8MCXwuGccl9
lb7Qr7nFSWMCAwEAAQ==
-----END PUBLIC KEY-----


Not Working

These ones haven't responded in a while. (They don't work)

These MIT ones are from, Source.
Last updated 2016-09-02 (version 6.0)
# cmu.ron.lcs.mit.edu
128.2.221.157:15217
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAGXsegzE6E/6j4vgzi3NqGSn2dz
W6gRxkuAL7PB8QmRqtG9ieSQjFB6cTYvkmp7x/LtHqlr9Fa6+/mT4Ma5oKU0RpgY
MyfYnEk0iiNWG2fj4mRpTscHfcEJfKP13OGAYP1ZuHksTXSYsaKfIwiVKMLgQ/hA
FHBSCs9X+bvVMgPOiEpxZXfaynOQ3TLGYtVywLRwW5yvlRq4E9z0rtvwR1bn1hVd
JaJ2Lw7kRVMCAwEAAQ==
-----END PUBLIC KEY-----
# convoke.ron.lcs.mit.edu
204.225.124.41:15217
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAHB9gHj3Zyx7u++wTffAsEuRJdj
CZSFocs5ZKVamm6O7ywtFCuPgxxYTr3GyrDKj2IBO05iXirOISyX0OtENvs829Xj
TbKqDgeN1ttDiJmszN939RvBdmzkmXi2zaOXPX3ral56hJOWjOs6NokeBo26ZHux
5k9g3AqFer5LNyDVgGrG5q7+INGodDSTYm2W5nvmi55U/pe7MmJCH7EEY1ObGPr1
7XqZeEbL4ikCAwEAAQ==
-----END PUBLIC KEY-----
# mvn.ron.lcs.mit.edu
66.232.160.65:15217
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAFTgU6nDuhi9TDkzypfgaW2ztQb
c9eFlVTiLfUkUCmrfn8FqNzxuYdl/Hin3/Usz443GAvOwx0pXocClZ7Xtve06w6H
xtuWMxAR0VMhywdzotTJAb/4a2btqHdrUlOZg6l7R66GbCupVWwyDQF7YBKarEGF
2v6mRM/WknwaEYVOMu7XDb6zkEf4MsxptQnY7PfNktMMcuhusYjko3IhFmlUl4lu
e+c3aFR35Y8CAwEAAQ==
-----END PUBLIC KEY-----
# hostway.ron.lcs.mit.edu
216.139.253.36:15217
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAFiENC/BwZXOfzDOed4Qbvjd/25
MixlCMlRUlfArJAvcjeBRmnY4fdQhi7/VH1qZeTQClegX1FMcuOORD29a4lks12W
iXrh1HxLKxCTkPp5ZLqP8OiNxWqHdEQyinh2ulYFXZHWMlXhlsQKV2T7VsmfS0rL
eukQAWpgGTXhACyZNpOQgjMm1vWEFaIsd2tT59Son7vxyCcaBoFCWv+zRW6kwaoK
i0KgnEHwKwcCAwEAAQ==
-----END PUBLIC KEY-----
perspectives02.exodica.com.ar
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAG8UxbiIPlZEWusfLqMxtehGUAe
r64r55U39CcUlpxQMlmNPtctHM852dpCcz6KE9yPw3MVceSaxmhVhkMLSF1mjiIp
pybmR3IeUG1re3rg1aRK1xy7KHl5aHSGfIle4q+JNuGkxNifxQdCSXLfVo6DCoxH
lj5o6Qg+fC642eWzd5zvKczzCxh0xEizjcQhYyBIZwqgCqNN/KCUci84dvTSITKJ
3dShYU0EpSsCAwEAAQ==
-----END PUBLIC KEY-----
crowdcouse.net:8080
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAGG5qAoxnLOsoHGG3zJs+W5Yn3+
AOMUzxhZqZsGbIxL46lw1wfgXJQ9MUbdzRjZjpd5TBInbNJbqQiQ0axD01MEgIgf
rCiG+ok7P85iKHdY2vHOnQ12AHDFODGJ/dICSVmLnaCsuoeG66pbNWs9JKTge32I
TJ3dULqzc04hO71j+QVZ3fpkuW49/xXzqz7iPvcGTIosc4S68pffd9dqACXw0KxW
DeYQnjW744sCAwEAAQ==
-----END PUBLIC KEY-----
195.93.242.152:8080
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAFlIJdwP+1xum2YSI1WHZ20lLBZ
Dpfm8u4yKydq/jv3sQItTo7csdunLcinI/Q5QLd3Ac6ZCnNCYjEwGNQrguYR0USQ
MQWDcBzOhsvLWktFsMXnLCvRak5/rHHuuh6NBwhnayLrJE3hFsTytDpfTxft0Ltm
BFaQHmrEYsYJK9XVPhXUeMaJhFcSyxux4VM2sWw8ADCTDfHIsPsM6Sacd2/kApdv
IWz3hA95qFMCAwEAAQ==
-----END PUBLIC KEY-----
I don't know much about this one, but it seems to have a good amount of history. Source
glisha.webfactional.com/perspectivesnotary
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAFFBupTSd/AtfkxMh3M53GhiAr1
C2uCJJmPQHoOzFqkYDziHCekm55uEPrKOiri3qOfHdDB7zYUAHBv7bA5ozhaA+3y
JdJ6V97u4wxuPOy+IsojK2JHAgKhvF/I5d9l6d4b3fZqzeRNhlaMI20SZlleSzVL
XKgsrK+EQUfRunS1NzlZtl657noMM/MirWkfpc3iYnqX+7bkEDO5cm8PsA27BUMS
nujfPWDgVHUCAwEAAQ==
-----END PUBLIC KEY-----
This notary server is a bit interesting as it supposedly stores the entire CA chain instead of just the certificate. Source
notary1.constructibleuniverse.net:8080
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAFzVqLz5qmyMwd4XuXGPtyDu0VO
hvfpt3fUJz/2bGWRDcWPIZw/1Gzj2VQjDSRXuAnjsnJY46s3P50HDYZ764AYvggd
vD8KjjNv5R5r6jW83bqJJPI2mRJR/Gu0iKZn7H7X8tKuL0qH5ukRAsonYj59qk2N
THZkBtiReqYoMv3+FzxJAbXM3rEp0+x2NzM9MeEA8JwYmCBqXZucDeL8N/WSvqOK
alVDUr82uj8CAwEAAQ==
-----END PUBLIC KEY-----
perspectives.hackcoop.com.ar
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAF3Ge/ghhCsDX4Y0PgWPMhvawGc
hlb460VvzaEcKKtQDOI4izZvfZokCY9TYzVH0T1tRJICV/FK7jr/Yj2D7BoT8mQk
KKxZaLSyUUr6Msl3n5ABGc8t/blUSvxYLRdLlEsPjSkYidbf9BI95wwB2ggJhrBL
nQIj0izhU0zkV5xV3YvMqBBnVsl5USjfBPrettNtGA6B3BVBeGGnYuMRBEKUTtSG
ODgBKw7jOQ8CAwEAAQ==
-----END PUBLIC KEY-----
ec2-54-66-132-58.ap-southeast-2.compute.amazonaws.com
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAGa3NpsLJPJt4+D2NoidbZq0sx4
ALtpaczKGdjgvtddQRq2ZC6vtdFKRtNy2Ml3pmLIVA2mndCQh1UCiG9OdJz2ZiZ2
BXWb82gyL3qpsSxUG41SyxZxvN4A7ABFASOolq3udNWr7ufIRVT2pCr0dV6IJOF/
/L6BJ8WzBeLVjID8SpnTc9wbwpGcvEWr0U6eEiJ/AyiClMYn2jtOnAW9l+rz1rR8
SJW79GNd6WUCAwEAAQ==
-----END PUBLIC KEY-----
stupidpupil-notary.herokuapp.com
-----BEGIN PUBLIC KEY-----
MIHKMA0GCSqGSIb3DQEBAQUAA4G4ADCBtAKBrAFmGJpjWUnO8MwvNeKXQnzh0Fo4
J9uBv/ij7Y1hcmarqj1aWI6Yo2KaPpZ5GolMsmqhkRvGxLqma6WU2Sy6mjatWmrx
iqYy5nZY+JeOkxRRzOiFxymTU+Z/x8VsFBHuX/D4fniGOUY2yIiu7iXG8W+DNEb1
GhfUzKZKyzsg7SzDKdC0MMkVvGzh9gaUlzdprh8FLdMOn9cJLuOLdwq2LQaNMc29
+dMxbklhVLcCAwEAAQ==
-----END PUBLIC KEY-----