I've been trying to give away some accounts for some time now with no success. Not sure if there's some kind of account-give-away scam that went around or something but they are my accounts I haven't used in years. Just hoping someone gets some fun out of them.
I'm betting that most or all of those have a TOS that doesn't allow an account to change owners. You might be unsuccessful because people don't want to end up on the wrong side of those companies and end up losing not only your account, but also their original account.
I would absolutely to love to have any of those with access to paid gamedev assets, as I've not bought any, or acquired any that were temporarily free, and will be relatively poor until after I win the gamedev lottery.
I'm not using Unity tho, so if any of those are vendor-locked to Unity (license or otherwise), maybe the next person should take those.