There are a lot of them on this section(gambling). Look at their original/first posts and you will have an idea if they've got it.
You know it that this will not help, checking every thread if they have signup bonus is very time consuming, sometimes the posted OP of gambling thread is outdated as well.
Well, upon using google here's my take
- Gamdom
- Stake
- 22bet
- ExciteWin
- MyStake
- Sportbet.one
This list came from this site
https://www.gamblingjudge.com/bitcoin-sports-welcome-bonus/
Disclaimer: I don't promote these mentioned websites, they may have recent scam accusations that might not interest you so better DYOR too.