Most webcams work on the Pi although some may have compatibility issues depending their certain chipsets.
I can't say I've ever seen thermal imaging cameras in USB form most i've seen are hand-held camcorder type with video output for a TV i.e. composite and cost around 2000+ quid.
As for nightvision webcams make sure it doesn't have an IR filter and illumination is infrared instead of the crappy white LEDs found on most cheap Chinese rubbish.
Ironically I actually modified one of my cheap Chinese rubbish to become a genuine night vision webcam, made easy since the filter glass sat glued behind the lens and surprisingly sensitive.