I have what tools I need to do the bearings on wheels, headsets, and bottom brackets for my bikes. I'd like to get what I need to remove the cassettes. (I hope that's the right terminology. Newbie, here.) I have a 77 Super Mirage, an 80 (or thereabouts) Grand Record and a Schwinn Collegiate and Suburban from the 70's.
I was overwhelmed by the tools I saw on Niagara Cycle's site. How can I narrow down what I need?

Your bikes would most likely have freewheels, not cassettes. There are about a dozen freewheel designs, so you need the freewheel tool that matches your specific freewheel. Then you need a big wrench, or a bench vise.

Here's some info:
https://sheldonbrown.com/freewheels.html

Can you post a picture of the cassette? is it cassette or freewheel? What brand it is? Shimano?

For freewheel shimano is this one https://www.amazon.com/Park-Tool-Free.../dp/B001B6RGXG

If it's a cassette from that era most likely is uniglide where the last cog is threaded (normal thread) and locks the rest of the cassette - for this you need two chain whips to undo the last cog.

Check this link to identify what your cassette looks like and what tool you need https://www.parktool.com/blog/repair-...ewheel-removal

The good news is there's really only about 3 common ones.
The bad news is I'm guessing your bikes are going to be one of each.

There's even a chance that the Schwinns have Schwinn-approved Maillard freewheels that use a now quite rare oversize splined remover:

Great info. Thanks everyone. I'll look into this and get back with what I had to get.

You have freewheels. How often do you think you'll need to remove them? It may not make sense to buy the tools. The last time I had a bike shop remove one they charged me $5.