Favorite Category

I have a revolutionary organizing scheme. I use the basic heart for everything that I'm keeping. Everything else just gets turned into manuals.

*Legendary heroes
*perfect or good iv 4&3 *
*5
*free units

Everything else is turned in manuals

I have a very less complicated favoring system.

hot pink heart goes to a unit with perfect ivs
if unit has no perfect ivs but does have good ivs I give them an orange heart
best iv outside of good ivs gets a light blue heart
bad ivs but only copy gets a green heart
yellow heart for TT and GHB/BHB units

the rest will be manual'd

#1: Normal 5*s that I get that are either good to keep or forgot to remove the favorite on

#2: Dragons (That's what it was originally for me, but with manuals, there's much less need to keep an entire section dedicated to dragons)

#3: Probably Limited Heroes (I like your idea)

#4: Probably Dancers/Singers (Another idea :))

#5: Units that I want to eventually use DC with (Goes with the colour)

#6: Units that will become apart of merges while...
#7: Units that will be merged upon (Generally with the right IVs or are already merged with/has decent IVs)

#8: Units that are +10, or close to, that reek havoc across the lands

My system is kinda JANK, but here we go.

#1: All 5* that have a complete skill set, are trained to lvl. 40, and have decent IVs
#2: All 5* that have a complete skill set, are trained to lvl. 40, but require a new IV due to really shite current IVs. (usually units that are regarded as good, but are crippled by the bad IV, like a -spd Ayra
#3: ??? (I haven't found a use yet)
#4: Units that I am currently training/plan to. a lot of these consist of units in need of Prf refines but I'm too poor on feathers. Consists of 3* to 5*
#5: 5* units that I don't use, but I like the characters enough to not fodder e.g. Merric (the ACTUAL FEH META)
#6: 5* units that I don't care for too much and can't decide whether to put them in (#5) or (#8)
#7: My efficiency grinder units that have the valor or exp. skills so I don't have to wait for 2x sp bonuses.
#8: Fodder. More specifically, any 5* with premium skills that I just want to sacrifice due to not meeting my previous criteria, or units that pity break me. e.g. Oscar (back when he was a 5*), Mathilda (remember this one too?), Gray, L'Arachel, Raven, Lachesis, etc.

Quick Iv check :
#1 : No boon
#2 : Atk boon
#3 : Def boon
#4 : Speed boon
#5 : Res boon
#6 : Hp boon
#7 : Free/limited/exclusive unit

Mine is:
Regular heart: neutral IVs or offensive neutral IVs
Hot pink: perfect IVs
Purple: second-best IVs (such as +atk instead of +spd)
Orange: one good IV
Blue: bad IVs

I don't use the other three colours.

Pink heart for personal favorite characters
Yellow heart for merge projects that are close to finished
Green heart for +10 merged characters
Light blue heart for characters I'm currently building
Blue heart for characters with weapons to upgrade
Purple heart for characters with best IVs
Hot pink heart for limited heroes

i dont do hearts

Interesting reading how everyone organizes their stuff. I remember seeing a screen cap of either Absolutely_Disgusting's or SaltLobster's (can't remember which one) barracks where he color coded each hero by game origin, thought that was a good way of doing this too

OG Heart: Other
Orange: Projects
Yellow: Unusable (-Atk)
Green: Unusable (-Spd)
Light Blue: Projects I've stopped/units I rarely use
Dark Blue: Units I use slightly more than ^
Purple: Favorites
Bright pink: I used to use this for TT/GHB/exclusive units, but since then they've been turned into manuals

1. Built 5-stars with decent or optimal IV's.
2. 5-stars waiting to be built.
3. Good IV units to be promoted.
4. Bad IV 5-stars.
5. Units needing weapon refine.
Don't use the rest.

1 for Units that need SP grinding
1 for 3/4 Stars with good IVs who will eventually be promoted
1 for 5 Stars I'm not sure I want to keep or fodder, so I'll favorite them instead of losing their unit potential as Combat Manuals
1 for Husbandos
And 1 for all other 5 Stars.
Don't know about the rest