CollegeBoard now supports "Score Choice" so you can pick which test date to send.
Score Choice - New SAT Score-Reporting Policy
See FAQ, you can only select by test date. Colleges cannot reject or opt-out. However you are expected to follow college policy, "as a matter of integrity".
I attended many info sessions. Many AO said, you should send all scores any way. Typically, AO would look at your top scores from all tests you have taken.
For example, if you have taken SAT twice and ACT, they'll look at all scores and pick the top score in math, top score in CR, and top score in WR. If you have taken many SAT2 subjects, they'll pick the top 2 or 3. Some AO said they like to see big improvement between tests.
Taking SAT more than 3 times is not advised unless you have to. I heard a AO said, for applicants with more than 3, they would average all your tests, instead of picking the top scores from different test dates.
Between SAT and ACT, colleges only require one. AO would like to see all, but it's up to you. However, as an example, if you got better math in SAT and better reading in ACT, then you should send both.