Try to google for collectors of music on cassettes and see if you can ask some different people about it. If 3 or 4 different people tell you they have no value than you'll have to decide if they still have value for you... or throw them away. It will than depend on how long your cassette player still lives. Those things are probably hard to repair or replace :o
The problem with cassettes is/was that they would wear out with time. Hence nobody would spend money now on buying them. Indeed, for music collectors, there are many albums that you only get on tapes if you go for uses music. But online / streaming music has killed that all.
Are these original albums or your taped collection?
Back them up digitally or something to preserve and archive their content, unless somehow you had already torrented and downloaded all MP3 copies of those music tracks and songs from the internet or something.
KEEEP THEM. Cassettes have gone the way of the dodo and their value will only increase over time at this point. Keep them safe. The number of surviving cassettes will only decrease from here. Fewer working cassettes = more resale value
I can't part with mine. They bring back a lot of happy memories. They are all in cases including originals. I keep them in my attic carefully boxed up. You just never know, one day they could become valuable.