There are still retro grouches who prefer thumbshifters and there are still options if you want to run a modern MTB drivetrain with thumbshifters. However nothing comes close in beauty as the Shimano Deore DX and XT thumbshifters of early 90’ies.
Shimano Deore DX thumbshifters are quite like the XT parts but slightly cheaper in appearance and lacking the positive click of the high end parts of the day. Even so, these are totally badass, you can not go wrong SL-MT62 Deore DX thumbshifters if you lounge for easier times when shifting your bike was a result of stretching your thumb or pointing finger in a passionate move of shiftering.
Even if you are not a retro –hipster alternative to the MTB world- dork you might find amusement in new ways of shifting. Perhaps thumbshifters will be the next big thing, the “new” singlespeed? Explore the same trails but with a new system to shift –Trails will never get boring again. Wow, I should seek a patent, or why not build a thumbie community?
If you are really, really cool you can mount these upside down, under the bar as a form of pseudo RapidFire system.
Vintage racers who thought they where way cooler than they actually was used to run them like this, they claimed they had a more secure grip of the handlebar during gnarly downhill racing, unfortunately this lead the way to horrible RapidFire+ and GripShift systems which eventually killed the better, more superior, industry standard shifting device for years thumbshifter.
But as said above, the thumbie is not dead.
It is actually alive -although maybe a bit worn- and you can kickstart the shifting revolution again for only 20 euro. SOLD!