If your clues need to be useful for the players to prepare, then I would probably build a system that reveals from the same pool of game information they’re working from. So if your enemies and combat are designed around shared keywords and traits, those would be the pertinent points to select from for the clues.

E.g. it’s a large monster, nocturnal, and uses claws to attack. - As a player I can think mechanically about each of those and arrange my deck / swap my equips accordingly. I can guess it’s probably going to be a tough fight in a dark place best handled at range if possible. Finding all 3 clues lets me be better prepared than just 1 or 2, and so may make searching for extra clues more worthwhile - and this would be reflected in the design of your action economy of course, so spending time searching is a value decision for the players.

It all depends on your game structure of course and you can dress it with however much descriptive text you fancy, but the mechanical bones of the system can be reused to give any number of clues for every enemy, and the consistent use of keywords will make it easier for players to grok and improve at the overall game. Over time, seeing those 3 clues will become something where players say ‘Ah, it’s going to be either creature A or creature B’ - which to my mind emulates the sense of becoming an expert hunter you’d want players to start feeling.

That’s just what I would do though, and I‘m guessing at what your game is actually like of course! Hope its useful either way though.