Oh, I couldn't help but to note people were listin', so I'll pitch in too!
(Note: Playing on JP, for a good while before NA launched)
147 Unique Servants
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No ascensions - 73
1 Ascension - 1 (Used Medea super early on, and then well, a certain SSR came along)
2 Ascensions - 1 (Working on Munenori)
Max Ascension - 78
Bond 10 - Heracles
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Grailed to 100: Summer Melt, Skadi, BB, Lancelot (Berserker)
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23 SSR Servants
22 Welfare SR Servants
43 Gacha SR Servants
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Among non-welfare SR and SSR servants:
NP3 - Siegfried, Vlad (BOTH), Sanzou, Helena, Kiritsugu
NP2: Suzuka Gozen, Tomoe, Atalanta, Bradamante, Nezha, Martha, Caster of Okeanos
, Caster Gilgamesh, Assassin of Shinjuku
, MHX Alter, Sitonai
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Servants at 10/10/10:
Summer Melt, Skadi, BB, Jalter, Mashu
Servants at ALMOST 10/10/10:
Nero Bride, Summer Jeanne, Tesla, Sanzou, Tamamo, MHX Alter, Qin Shi Huang, Elizabeth Bathory, Sakamoto Ryouma, Rider Kintoki, Nitocris
If anything, I grailed Zerkerlot just for the sake of making Double Skadi loops with him more reliable. I only got him for the first time on the recent SR pick ticket we got, and while he's a joy to use for looping outside of the cases where I can't use the usual DSS systems (all of them aided by Nero Bride), just NP1 isn't enough to match the consistency of my other loopers (Or my absolute last resort loop option, Double Tamamo and Bride on Summer Jeanne). For example, the current Xmas event with Nightingale as the welfare has its box currency dedicated node being Lancers, and without a loopable Saber, I'm stuck using Zerkerlot. However he can't kill the second wave without extra buffs/debuffs, and more importantly, at Level 80 he can only wipe the third wave with either a Brave Chain, or having his one Quick card on that turn. While NP2 would be a lot more significant in the damage dealt, at least fully grailing him means that both Skadis can hit their crits to help with finishing the wave.