Up until 1933, there was an instrument called "the pauper's oath". If you were on any form of public assistance, you were required to sign that document and give up your right to vote until you were producing again.
The Great Depression killed it, and then the 26th Amendment finished it off for good.
Of course, I left out the main category I’d like to prohibit from voting for the reason stated: Federal employees. I’m thinking that our overwhelming majority in the military is more than outweighed by a monstrous Federal bureaucracy comprised primarily of leftists.
24th Amendment — how in the world did that ever get passed?