A little off-topic but I was having a dream about 2003 rpg maker minutes ago.
Interesting thread, I should look into games made in those engines. Reminds me of games made in Cave Story engine.
For Solarus in particular, I've been inclined for the longest time to say that the best thing to come out of it is the game the engine was made for. Yarntown is a serviceable tech demo of sorts. ZBoM is an overambitious, bloated mess that throws almost every obscure Zelda race they could get their hands on in a blender alongside some OCS and unrelated SNES sprites, has a tedious stamina system you can only manage well by buying food, makes you wait for the time of day to change, doesn't limit the number of rare items you can collect despite the final reward threshold for each being fairly low, takes place in an almost unnavigably large setting that becomes manageable at best with the fast travel ocarina, locks major QoL features and items like map and fast travel behind easily-overlookable goals, and features horribly inconsistent, often-lacking dungeon quality. Return of the Hylian: SE is a faithful recreation of a fangame with very questionable design decisions and somewhat unpolished enemy behaviors. I haven't tried the one that's being sold on steam. Mystery of Solarus DX and the other 3 Solarus Team quests are really quite good.
You probably want to download the last major release of the engine rather than current because engine changes in the most recent major release can cause old quests, virtually the entire featured quest list on the website, to break. Technically, you can unzip any quest, import it into the new editor which prompts you to automatically convert it to the new version, and test and debug it, but that can be difficult, obtuse, and tedious, especially if you just want to play the games.
ZQuest Classic. The one fan forum/quest host I know offhand is purezc.net, but there are probably others. There are so many different visions and completely custom graphics, items, mechanics, and enemies that have been put into these quests. Most of what I'm about to mention have a story focus too. Metroidvania with supernatural mystery, an air of weirdness, and many different flavors of projectile attacks and spells, plus replayability via multiple player characters whose respective routes have different boss fights? Hitodama, Yuurei, Yuurand. Gets really hard, harder than vanilla Zelda 1 enemies could ever be, has an odd setting, and has novel and creative boss fights that really highlight the capabilities of the engine? Umbral Cloud, Isle of Rebirth. Mechanical weirdness and a postgame? The Slipstream. A twist on the original Zelda 1 setting, mechanics, and aesthetic? The Depths of Malice. Something a little less out there and closer to the original quests? A great many of those exist. And there's much more to speak of than what I just highlighted.
The quests can also be filtered based on their assigned genre tag on the site I mentioned. You might need to download multiple engine versions for this one too on account of that the tool has been in development for more than two decades at this point and isn't entirely/hasn't always been backwards compatible with older iterations. Also note that starting a playthrough/save of a custom quest is a mildly unintuitive process.
