Free art is free art but so many of these are weirdly cropped, low quality, or badly compressed. Also the categorisation is non-existent, which is bizarre given all these creatures do actually have names. Some images are even duplicates of other pictures in the same art pack.

This is legitimately the worst 5e supplement I've ever seen in my life, and the fact that it's performed as well as it has depresses me. The bottom line is that this is a very bad product you should never buy, but I'll break down its many failings into a numbered list.

1. Reason for existing. Strahd does not need to be CR 27. He just doesn't. He doesn't need 29 AC, he doesn't need resistance to all damage, he doesn't need to make 9 attacks per turn (4 base, 3 legendary actions, monstrous form, and haste), and he especially does not need to be more powerful than archdevils and demon lords. The regular Strahd, used intelligently, in Castle Ravenloft, with minions, will wipe the floor with your players plenty. You don't need this product.

2. Fun. Your players will not have fun fighting this statblock. They will not enjoy missing every attack because he has 29 AC. They will not enjoy whittling through his effective ~350 hit points, with 30 hp of regeneration a turn. They will not enjoy you permanently cutting their arm off as a legendary action. They will not enjoy being permanently stunned with no roll by a DC 22 Power Word Stun. They just won't. Moreover, you will not enjoy running this statblock. If you thought regular Strahd was too complicated to use effectively, wait until you get a load of the A4 page and a half of statblock that this monstrosity is, complete with impossible-to-parse walls of text, an additional half a page of magic items you have to understand, and a full page of completely opaque and complicated spells you have to learn how to use.

3. Proof reading, spelling, grammar, punctuation, and math. The whole product is riddled with capitals where they shouldn't be, lowercase letters where they should be, spaces after commas, no spaces before commas, mispelling names (Mordenkainen is mispelled in two different ways in one paragraph, and not capitalised either time) (also Strahd is repeatedly spelled "Strand", and often also not capitalised) and just terrible, terrible spelling and grammar. Quote: "As the lord of the land, Its totaly unacceptable for strahd to not have magic items equiped when he fights to kill his en-emies." The math is also atrocious. Strahd does not have a proficiency bonus listed, and his attacks, saves, passive perception, and spells all appear to use different proficiency bonuses.

TL;DR: Product bad, do not buy.