I'm thinking of selling off some of my tv stuff, I have several round color crt's, any suggestion?

what would they be worth, you can't go down and buy these anymore.

I would contact earlytelevision.org
https://www.earlytelevision.org/contact_us.html

Need more information. Make, model, year, condition. Fully restored and working or as-is?

So what numbers do you have? What manufacturers? are the new? Are they pullouts? Are they in boxes or what? Are they pick up only? Do you ship? There are just so many questions...

Raw spare CRTs or complete TVs?

I've seen complete roundy color TVs post 1960 go for free to $400 depending on condition cabinet style and local market conditions. Pre - 1960 free to 10k.

Raw roundy color CRTs free to $300 depending on how it tests and condition... 21CYP and 21AXP more. 15GP22 around $4k if capable of making a decent picture.