Tunnels and Trolls recently moved home to Kurated Korner, sort of a shopping portal and company that owns many different smaller companies and built a shopping portal around the collection of diverse parts. It isn't a dedicated game company, which would be very nice, but this is the next best thing since T&T isn't a game that needs a lot of redesign and support.
The Goodman Games Example
The closest modern game to T&T is Dungeon Crawl Classics - a large core book that never really needs to change except for unique variant covers created every year and put out on Kickstarter, plus a dedicated line of modules. Goodman Games does a great job doing the online store and module support, and the DCC & MCC modules are highly entertaining, with fantastic art, and very fun to read and play.
I would love variant covers for T&T, and I would really love new adventure modules to be created.
Goodman Games does an incredible job with community support, road crews, the sales of 3rd party books, swag, and convention support. You feel like you are a part of something huge when you play the game. That sense of fun is there, and I could wear a DCC t-shirt and instantly connect with others and that I am a great person worth getting to know, hanging out with, and playing games with.
But the most incredible thing with T&T is the books are still being kept in print and sold, which is keeping the game alive. Even the MSPE hardcover is here, which is a very cool thing. So while not ideal, I am happy it has a home, and the game is being kept alive.
So I had T&T on a storage shelf, and I was doing some cleaning here and found a spot for a shelf where I could put my "quirky games" on. Of course, DCC and MCC got the top shelf of that collection and became an instant shrine to quirky, silly, good fun. On the second shelf down, I put a collection of odd OSR and other games, and I put T&T on there since the game fit in.
T&T is the perfect "fistful of dice" sort of game. The game doesn't really care too much for special moves, class abilities, action surges, or a vast number of classes and archetypes. Balance is relative; you can play a fairy mage with very little strength and a lot of magic. You can play a brute who smashes everything. You can play the dead-shot elven archer.
And the more dice in your attack, the better.
And the ability scores float. You can get permanent (positive and negative) ability score changes during adventures, from gear, and at any time, your stats can be modified permanently. Your level depends on your highest prime stat, and you use XP to continually increase them. You can find a ring that gives +5 luck. You could act like a fool before the King's Ball and suffer a -10 charisma. There is no master level chart; you continuously improve stats and just "go as you go."
T&T is also a great "pick up and play game." My recent experience with 5E was a 2-hour session to design a character, and I felt like I wasted my time for what I got out of the process. With T&T or even C&C, I could spend 5 minutes designing my character and get playing. This kills 5E and Pathfinder 2e these days for me; they are so complicated, with so many books and options, that you go down a rabbit hole of rules and options for dozens of minor bonuses to specific situations. You get a character who is no better off than a B/X 3d6 down the line, except you have a dozen lines of special modifiers for random things.
Computer Needed? Not a Tabletop RPG
And with 5E or Pathfinder 2e, you often need a computer to design a character. I am ready to say that no pen-and-paper game that needs a computer-assisted character generation program can call itself a tabletop RPG. Sorry, you are a computer game now with tabletop interactive elements. I don't have two hours to pour into a character anymore without automated tools, and for a minimal benefit. The options and special abilities I got were trivial, and a few minor modifiers to specific combat situations.
And my B/X character took 30 times less time to create and gave me the same gameplay. A T&T character would be the same. And in T&T, if I start with a score of 4, I can spend XP to raise that as much as I want with no real penalty or loss of advancement elsewhere. I am not "wasting my first four character levels" trying to get that to a score of 12; I just get XP and raise the ability score how I want. Your level is based on your highest prime stat. You could be level 1 forever and raise a non-prime stat to a score of 100. T&T does not care, work on your character however you want, and have fun.