My list is quite long, so bear with me.

Bunyan for obvious pancake reasons. She is the strongest berserker there is and cutest to boot. She secretly is a saber-face but ended up being her own Bunyan-face.

Euryale cause she is the sister of the best Gorgon. (I mean Stheno)

Caesar. I am still biased from Asterix and Obelix. I really liked him there and he is quite the same in FGO, too.

Spartacus. He can farm. Like really, he always does enough damage to kill with his NP.

Gareth. I like her so much that I made a Japanese account just to get her and grail her to level 120. There is still a video where a late member of this community used my Gareth to solo the Gilgamesh CQ.

Columbus for his reactions.

Boudica is a special case. I looked at her and grailed her like I was in trance. Now I try to do a funny healing setup with CCs. I need her to become a Grand Rider in hope for amplifying her tankiness and healingness.

Gilles de Rais caster. He is a foreigner in a caster outfit and the most COOL ever.

Mata Hari for crit buff fun.

Darius. He was my very first servant I got back then. When 3* and 4* servants were in the tutorial banner. I still love him.

Mary Anning for being a dino lover with a dog and thunder abilities like Thor. She is the closest we got for Thor.

Paris cause I like archers with guns.

Bedivere, Bartholomew, Bunyan, Gareth

They're my most skilled low rarities also i favorite ones

Mori, cause cray cray, handsome, tall and loyal is my personal Cryptonite. For a me as girl, his overly protective manner is so hot holy shit.

Mandricardo cause he is my friendo. He a chill guy.

Izo, cause i do like my cute alcoholic Manslayer with his dapper costumes and fat damage.

Asclepius because he doesn't take no bullshit from anybody and i respect that.

Costume dress for Mori when?

Honorary Waifu mentions: Gareth best (bronze) girlie. I also like Ushi, Medea and Xu Fu.

Edit: I usually slap an Kscope on the ST bois to use for farming. And in some boss fights if i am feeling big brain.

Mori & Chacha interactions are great.

I have 8 NP 5 copies of Asclepius (so 40), they're all 10/10/10 and 1K Fous so probably him, will also be my Grand Caster

Man, I remember it took me over 300 SQ to get a copy of Asclepius, fun times.

For me it is Arash. I used him a lot in the last NA Lotto Event.

Charlotte Corday is fun to use

There's also Asclepius but I don't see myself grailing him

Sasaki Kojiro & Cu Caster man they are great