Haven't played all of them, but I'd rec:
>Disorientation - one of the most famous FMs with its impressive sprawling City
>Heist Society - the quintessential mansion FM, very straightforward objectives but well-designed map, with many points of entry
>Black Frog campaign - 5 mission campaign with custom NPCs, some custom music, kino 2nd and 5th missions, and an intriguing plotline
Honorable mentions: A Better Tomorrow (too damn scary), Conspiracies In The Dark (nice dark atmosphere), The Tower (very small but comfy), Mission X (It is a very large casino)
>Are they all really worth playing
Generally yes but some of those FMs are... problematic, to say the least. Like the Rocksburg FMs with its obtuse objectives or the Calendra missions, which feel dated and have that cringe scene of Garrett having sex in one of them.
>did someone just grab a bunch of random ones
No but that pic is very old and it's missing some very good FMs, like Violent End of Duncan Malveine, Endless Rain, Ten Little Taffers, Midsummer Night's Heist, Lord Alan's Series, TX2 Campaign, Into The Odd, some of the winners from the T2 20th Anniversary contest, and that one FM campaign that takes place in a pirate island at daytime.