I can’t think of an easy way to find this info so I’m being a bit lazy and asking the geniuses at e4.
Obviously Legendary Collection Reverse Holo is a full 110 card set of holos. What other sets have 100% of the cards in the set as holos (reverse or otherwise)?
Since you weren’t too specific
PPP Promotional Cards Set - 7 cards
10th Movie Commemoration Set - 11 cards (12 + Darkrai)
11th Movie Commemoration Set - 9 cards
2010 World Collection Pikachu Set - 9 cards
*Bonus set as 31/32 are holo*
PLAY Promotional Cards Set - 32 cards (31 Holo)
If you include reverse holos, the list of sets that AREN’T all holo is probably smaller
If reverses count I’ll throw in most Japanese Concept Pack sets like Pokekyun and the entirety of the English ex era - especially the “stamped” reverses, since the basically are regular holos with pretty cool patterns.
English
Legendary reverse
Expedition reverse
Dragon Vault
All McDonalds
25th
Most other sets do have a reverse line but most times the Holo (like the H1 H2 in Aquapolis)or the LVx of GX or EX (like in Ruby/Sapphire) are not in reverse.
Dragon Vault
Detective Pikachu
As noted by some above, if you’re looking for a set that is completely uniform in its holos, you won’t find it in the typical expansion sets. Dragon vault is, and then there is expedition, which had reverse holo variants of holo cards, while the other e-reader sets had seperate holo cards that had no reverse holo variants. Double Crisis might count too, if you consider kyogre and groudon ‘reverse holo’.
sorry i wasn’t specific. I meant any set in which every single card in that set is entire holo in a consistent way. So the entire set is reverse holo, or the entire set is cosmos holo etc. Hope that makes sense 
Just thought it was an interesting exercise. thanks for responses so far!
Celebrations, along with the Classic Collection.
Creatures Corporate History