It depends on the level of the character, considering a 600+ MS (This level because that's the required one to use BIS items), using set and skillwheel all focused in magic level (Ignoring protection needed to specific respawn) this is what we got:
SLOT | ITEM | ML |
Helmet | Arcanomancer Regalia | +3 |
Shield | Arcanomancer Folio | +5 |
Ring | Charged Arcanomancer Ring* / Green Plasma Ring | +2 |
Wand | Sanguine Coil* / Soultainter | +5 |
Boots | Sanguine Boots | +2 |
Armor | Soulmantle | +4 |
Legs | Soulshanks | +3 |
Amulet | Enchanted Theurgic Amulet | +3 |
Imbuements | x2 Magic level Imbuement | +8 |
*Sanguine Coil and Soultainter both give +5 ML, but Sanguine Coil has better modifiers.
- Consumibles: Tropical Fried Terrorbird +5 (for 1 hour)
You cannot combine Food + Potion.
In total with this set, skillwheel and using the food you can gain: +42 ML
Also, if you have 50% Loyalty on your account, you will an extra around +5 ML. (This number also depends on your base ML)