In no particular order

Ruth Badger
Saira Khan
Kristina Grimes
Simon Smith
Raef Bjyadogudhfifu

Tre (absolutely hilarious)
Ansell (loved him - good solid nice guy)
Lucinda (sweetie!)
Raef (i love his general coiffed-ness)
Naomi (i thought she was the most decent in that series)

would also consider Simon (this series and series 3), Tuan, Jadine, and Lohit

In no particular order:

James (S1)
Miriam (S1)
Ansell (S2)
Simon (S4)
Raef (S4)

I'd also mention Ruth and Tre - they weren't always nice but they were great to watch and they had talent.

In no order

James Max - a complete gent, lovely man
Miriam - I'm still annoyed about her sacking
The Badger - loved her, very likeable once you got used to her
Tre - another one who took some getting used to, but he was actually hilarious and likable
Raef and Lucinda - just both so calm, capable and generally lovely