Lots of terminal commands come with tab-completion out of the box (start typing a command, hit tab to autocomplete, hit tab twice to bring up a list of available options), or have tab completion scripts you can install after the fact.

Lacking tab completion, any worthwhile terminal commands will at least support a -h/--help flag that will print out a help menu summarizing the different options, or you can open up the man pages to see even more detailed documentation with man [whatever terminal command]. If the terminal command doesn't have either of those, I'd recommend against using it.

I highly recommend zsh. It takes a moment to setup initially, but you can use oh-my-zsh to just skip that part and use one of the many, many presets, and it supports plugins, of which there are many. It gives you tab support for so many popular commands, you will never need to remember them, and it has a lot of small improvements that makes your terminal life a breath. For example, if you do cd tab in bash, it will give you a list of subdirrectories. If you do the same in zsh, it will give you that list and a cursor that you can use to navigate said list, so instead of typing the dir, you can do cd tab tab tab enter