I signed a transaction on collab.land to join a community. I wanted to know if this allowed them access to take funds off my wallet?
Welcome to the MetaMask Community @tomassive!! 
Great question!
Yes, when you connect your MetaMask wallet to a web3 site, this allows for that site to have access to that account/address. Which tokens it has access to is dependent on what the site requires. Some require that they have access to all of the tokens associated with an account/address, others request access to specific tokens. This is called a token allowance.
You can view what sites have access to an account/address on Token Allowance Checker.