Here are paraphrased versions of "Thanks #BOB, Welcome to BOB":
Appreciate it, #BOB — great to have you with us!
Thank you, #BOB! Glad to welcome you aboard!
Cheers #BOB, and welcome to the family!
Much appreciated, #BOB — welcome to the crew!
Thanks a lot, #BOB! It’s awesome to have you here!
Would you like it more casual, corporate, or community-style?