Pokémon Adventures Red by Kusaka and Mato. Definitely one of the better starting points.
There are several other starting points if you’re interested in reading Adventures in arcs rather than story (in chronological) order:
1. Red arc, the first one: this is probably the best adaptation of the games, and is reasonably similar to them in terms of plot (there are a few surprises but for the most part it’s generally like the games)
2. Gold/Silver/Crystal: now hear me out, I know this is very interconnected with Red/Yellow arcs, but I actually started reading it first and then reading the first two arcs once I began to love the Kanto characters. Definitely something you can do, although I don’t recommend it because you’ll get a LOT more out of this arc once you read the first two. It does have great rereadability, though, so you might want to reread it after reading Red and Yellow arcs. This one is pretty different from the games, with Gold, an impulsive punk, chasing down Silver (who is pretty much like the games), and ultimately running into a totally new villain with a totally new agenda. This arc has the best final few chapters of almost any arc, featuring a Gym Leader exhibition match that is amazing and a GREAT final fight scene.
3. Ruby/Sapphire: this one is pretty self contained, besides the ending. Follows Ruby, a coordinator who is very vain and focused on beauty, and Sapphire, a wild girl who loves to battle, as they compete to get all the ribbons/badges within 80 days. One of the best character arcs in the series with Ruby here.
4. Diamond/Pearl/Platinum: This is my personal favorite and recommended starting point if you don’t want to start at the beginning. Basically a Buddy Road Trip comedy but with Pokémon. Absolutely great. I can’t recommend these two arcs enough. The end hints at both HGSS and BW, but other than that you can easily read this first and it is self contained.
5. Black/White: Kind of like Adventures Red in that for the most part it stays reasonably similar to the games, with a few twists. The big difference is that White is a filmmaker. I don’t recommend starting here as it ends in a HUGE cliffhanger that still (infuriatingly) hasn’t been resolved in BW2.
6. XY: Again, very much like the games but with a few added twists (such as Vaniville Town getting totaled by Xerneas and Yveltal). A good arc, but not the strongest imo. I wouldn’t recommend starting here.
7. SM: I am not up to the current chapter yet, but this has been pretty good to the point I am. Moon is a pharmacist and Sun is a courier obsessed with money. Hijinks ensue as Sun does the island challenge.
If I had to recommend one, I would recommend DP. My recommended reading order if you don’t want to start at the beginning (which I highly recommend) is as follows:
1. DP/Platinum
2. Red/Yellow
3. Gold/Silver/Crystal
4. Ruby/Sapphire
5. Firered/LeafGreen which goes directly into Emerald
6. Heartgold/Soulsilver (which, if you start with DPPt, the ending of which will be teased, but I promise you that it makes more sense if you read GSC/FRLG/Emerald)
7. ORAS
8. XY
9. BW/BW2 (because hopefully that will he finished by the time you get here lol)
10. SM (Wait for them to come out in volumes if you ask me)