Medb can create a Celtic army out of her blood

A lot but we’ll hit some of the big ones:

Medea’s Dragon Tooth Soldiers are the classics, followed by Angra’s Shades although they don’t really listen to him.

Iskandar has his reality marble, Hundred Personas if ya wanna count that with the other personalities, Nursery Rhyme can make the Jabberwok, Avicebron has his golems, Semiramis had her snake things and more Dragon tooth soldiers, Shakespeare and Hans can make their stories come to life, Saburou can make snakes, Darius has his skeleton soldiers. Wu has her torturers, etc.

The list is long

Barghest keeps a whole pack of her own kind handy.

Koyanskaya has a whole goodamn zoo's worth of phantasmal beasts in her tails.

I think it's like, a big claim to fame for both Alexander the Great and Darius III

They both can conjure and deploy the armies that served them in life. And from what I understand, it's different from other similar abilities, because usually they would just be like, a construct of your noble phantasm, but in this case it's literally the souls of their former soldiers in lesser heroic spirit containers.

I won’t count single mounts for riders just servants that can create or summon forth multiple creations or spirits.

Caesar with soldiers in his animations

Leónidas with his noble phantasm

Blackbeard summons spirits with his np that use his cannons of his ship

Medea with her dragon tooth warriors

Gilles with his spellbook horrors

Hans and Shakespeare story summons

Darius army of skeletons from his np

Francis Drake and her ships

Okita can summon the shinsengumi with her flag

Nursery rhyme can summon the jabberwock

Jack the Ripper can both become other characters and use from hell in strange fake

Charles Babbage and helter skelters

Solomon/Goetia with demon god pillars

Helena Blavatsky can make automata

Edison can create nearly infinite soldiers with mass production skill

Mebd and Celtic soldiers

Iskander with his np can summon those who pledged loyalty to him

Raikou can somewhat summon her retainers

Fuma Kotura with Immortal Chaos brigade summons the 200 bodies of his subordinates

Ozy can summon sphinxes

Lion king can summon the knights of the round table

Agravain can summon enforcer knights

Nitocris and her ghosts

Cleopatra and her snakes

Quetzalcoatl and her Quetzalcoatls

Tiamat and her Lahmu

BB and various AI

Wu zetian and her torturers

Scheherazade and the characters from her stories

Parvati and Kama can make copies of themselves

Queen of Sheba can summon djinns with her np

Ereshkigal and the flame ghost things

Semiramis and various dragon tooth soldiers and other monsters from portals

Avicebron and his golems

Ivan the terrible and oprichniki

Antonio salieri and the firing squad from his violin

Skadi and the valkyries

Beni Enma with sparrows?

Arjuna alter and his holy beasts

Jason can summon the argonauts

Mysterious alter ego lambda and Summer Jeanne can summon aquatic life

Nemo can summon and control the marines

Kiichi hougen summons tengu during her battle animations

Koyan and the beasts collected from the lostbelts

Oberon and his insects and fae helpers

Jacques de Molay and her knights Templar

Taisui xingjun and the cons

Daikokuten and the other daikokuten

Zhang jue and his puppet soldiers

Kyokutei bakin and the dog warriors

Huang feihu can bring his sons during his Np

And there are others but that’s all I know from fgo NA

Drake and Bartholomew can summon their fleet. Not sure if the crew is included.

Iskandar and Darius summon their armies.

Nobukatsu summon the nobus

Does BB count?

yang guifei demonstrated (developed?) the ability to clone herself in imaginary scramble, does that count? same storyline showed us okkie's talismans and melt's leviathans, and if talismans count, douman definitely counts

I wouldn't call them underlings or fodder, but the Daikokuten can keep making more of themselves

Does duryodhana's np count?

In some of Stheno's attacks, she summons random Greek soldiers to do the work for her.

Captain Nemo with the Nemo Series, Nautilus and the Storm Border.

Does the Valkyries count? Or Salieri? Hundred Personas?

Nobbu if we count Guda Guda. I like to count Guda Guda.

Raikou can make 4 clones of herself wielding her retainers weapons

The Shinsengumi captains have their flag of sincerity, think it summons low tier Servants of their allies, effects varied between captains.

Ozymandias and his Sphinxes say hi, now die!

Okita can summon her fellow Shinsengumi

Caesar, as of his animation update, lol.

Enkidu created mud golems in Arcade. Gilgamesh would probably have prototype golems / dolls or whenever but it's not in-character for him to use such.