for the remaster, the CD reading system is replaced with a built in searchable Song List. This is how you can play it on Mobile, Switch, Steam etc. The Song List doesn’t exactly equate to original CDs (the function is mechanically different) but there are a handful of entries that equate to their originals (this accounts for about 0.01% of entries within the 664,909 that create their original monsters.
The good news is, Everyone now has access to the entire game and can raise any monster they want to (once they’re unlocked, of course), and the Song List is 100% solved and published. You can Random Button if you like the surprise, but if you want something specific, you can just view the published Song List, Pick your Monster Main/Sub, then pick the Title/Artist suggestion for the variant you want. :)
Monster Rancher has made a return!, in a sense.
“MR1&2DX” a “Remaster” is on Steam, Switch, and iOS. This came out in 2021. (It’s mostly the same game, just with a searchable CD Database/Song List instead of physical media, upscaling, both JP and English monsters in the same game, Enemy monsters raisable, extra freezer slots, fast forward, instant loads etc. a bunch of QoL stuff).
Also there’s Ultra Kaiju Monster Rancher (This one is on Switch only) that came out in 2022… a Crossover franchise of raising Ultraman Kaiju that plays like a mix of both MR1 and MR2
And LINE: Monster Farm, came out in 2023. A JP only gacha game, though there’s some hopium that it will be released in the west eventually.
There’s a huge Monster Rancher community and Discord that even holds public tournaments with varying formats and stat-cap limits. It’s a lot of fun!