Based on this site, it looks like there are just 15 games.
| Game | Availability | Notes | 
| The Binding of Isaac: Rebirth | eShop only |  | 
| BlockForm |  |  | 
| BRICK RACE |  |  | 
| Dragon Fang Z: Ryuusha Rose to Yadorigi no Meikyuu | eShop only | A 2019 New 3DS port of the 2017 Switch game. | 
| Fire Emblem Warriors |  |  | 
| Futuridum EP Deluxe |  |  | 
| Lifespeed | eShop only |  | 
| Minecraft: New Nintendo 3DS Edition | Both |  | 
| Pinball Hall of Fame: Williams Collection |  |  | 
| Pirate Pop Plus |  |  | 
| Pixel Hunter |  |  | 
| Runbow Pocket |  |  | 
| Silver Falls: 3 Down Stars | eShop only |  | 
| Wind-Up Knight 2 |  |  | 
| Xenoblade Chronicles 3D | Both |  | 
I only ask, because that console is selling used where I live for about 200-300, but the 3dsxl is only about 100 if you find a good deal usually around 120.
Wasn’t the remake of Mario & Luigi Superstar Saga New 3DS exclusive?
No it isn’t, just checked my copy to be sure. I played it on my regular 3DS XL.
Ah good to know! I think I avoided picking it up before because I thought it required the New 3DS. I’ll look for it at my local game store next time I visit.