Xiao Jijin, the simulator you want.

GBA emulator. Registration is free, but signature is required. Students who have cracked their phones can ignore it. I don't think it's necessary to post the GBC emulator because I haven't found a fun GBC game yet. I recommend GBA games. I'm sorry. I have a lot of GBA games on my phone, but I've only played them for a few minutes each. The ones worth recommending are Dragon Ball Z: Goku's Legacy 2 (Note, Goku's Legacy 1 has a problem, and it goes wrong halfway through the run. Goku's Legacy 3, which is Buu's Wrath, is in English, so students who are capable can play it, but I can't stand it anyway), Dragon Ball Z Dance Battle (note, it's available on mobile phone simulators) One problem is that you must not pop up the simulator menu when running the game, as this will cause button incompatibility, that is, you have to press three buttons to release a special move, but it cannot be released if you press it hard. In fact, it is because it is stuck during the running process and its buttons are slow to respond), Dragon Ball Goku Adventure. Among them, Goku's Legacy 2 is a role-action game with 4 characters, and it is the story of Dragon Ball Android (Super 2 Gohan is super strong). Maiku Gekito is a fighting game, and it seems to be the best fighting game in the GBA. I don't know, because I don't like fighting games like One Piece or Naruto, so I only played Maiku Gekito. Goku Adventure is a side-scrolling action game. At the beginning, you can only choose Goku, and it seems that you can also choose Piccolo. I haven't been there, so I don't know yet.
Recommendation: Ace Attorney series (three in total), which is a detective reasoning game. The plot is very good. I finished the first one. I highly recommend it.
Pokemon series, Fire Red version, Leaf Green version (I heard that the two versions are similar, I have only played the Fire Red version, which is the GBA reprint of the first Pokemon, and the original is the GB version), Ruby version, Emerald version, Sapphire version (I heard that the three versions are similar, I have only played the Emerald version, which is the third part of the Pokemon series). The second gold and silver version is a transplant, so I haven't downloaded it. I don't know if it's good or not! China Entertainment's Pet Kingdom is just like this. If you like it, just go and play it and see what the original version is like.
The Chinese version of Super Real Mahjong Alumni Association, this, ahem... students with low points... can try it... Also, mahjong beginners can also try it, it is easy to fool the tiles, anyway, I, a beginner, passed the level. (Quietly, there are a lot of CGs, so it's worth shooting)
Robot Wars series. It's a strategy chess game with many parts. I haven't played it carefully, but it feels good.
Fire Emblem series, the ancestor of strategy and chess games, now has a GBA version. The graphics are amazing, so I recommend it.
I have only downloaded two games in the Yu-Gi-Oh! series, one in Chinese and one in half-Chinese. They are passable, but they are too big, and there is no data to download the other versions...
Note, the Mermaid Princess is not fun, it is a dancing game, which is very boring, and maybe because of the mobile phone simulation, the songs are all out of tune, which is simply noise! Don't forget about The Sims and Grand Theft Auto, they may be too big to play (I'm nostalgic for my 64M...) Castlevania series, side-scrolling action games. Do you like China Entertainment's Demon-Slaying and Demon-Slaying Record? China Entertainment modified it based on this. I am not interested in this type of game, so I have never played it. It should be good!