From memory, Roland and Yamaha were popular standard midi modules
on College music tech courses I attended back in the 90s..

Just good general purpose affordable modules..

I still own Alesis, Akai, and Yamaha modules somewhere in the house.
But none have seen light of day for nearly 20 years...

As for specific models and variations,
google obviously provides reviews and links to user groups.

I'd run an old Win XP PC [not conncted to internet]
loaded with era correct midi utility software
to get best out of such modules.
Downloads can still be found.....

Ps.. my Yamaha Sampler which retailed at near £1000 in the late 90s
probably wouldn't fetch even a tenth of that now...

Prices for much of this old tech are definitely in favour of buyers...

By coincidence, I'm having to re-educate myself in such midi matters just recently,
as I'm finally putting together a decent music DAW laptop
after being distracted by family & health concerns for far to many years...