Top 5 for now 
Reasoning is that I enjoy them a lot.
Oscillator: Frap Tools Brenso
Filter: Doepfer 12dB SEM
Envelope/VCA: Cosmotronic Delta-V
Mod Source: Dnipro Modular Krait
FX: Intellijel Rainmaker
Honorables: Disting mk4, Turing Machine, Cosmix
Also Doepfer A-121-3 12dB multimode is a great filter. I like it for percussive sounds: high-pass gives nice hats, band-pass is good for snares.
Doepfer A-145-4
4 LFOs which can run pretty slow (4 mins) if you want them to. I use it in almost every patch to add a little movement. Cheap, takes up v little space, provided youāve got the depth in your case. Canāt be reset or anything fancy, but I quite like that; forces you to go with the flow.
Bubblesound uLFO
Now this one can go very slow (an hour or so). I first got into modular to generate drones, & itās wonderful for helping with extremely slow changes. Can also act as a pretty tasty oscillator; the shaped sine output sounds v nice.
Dave Smith Modular DSM03 Feedback
One of my favourite parts of the Evolver broken out into its own module. It mildly troubles me that itās digital under the hood, but it sounds great. Can be used to mess up existing sounds, or generate weird hi-hats with its triggered noise source
Rossum Evolution
Lovely moog-ish filter which sounds nicest clean imo, but can do dirt if you want. The killer feature for me is the q compensation, which lets you crank the resonance without losing bass. I think e-mu samplers did this by default, and those were the first filters I worked with. Iāve always been rather disappointed with the drop off from most analogue filters. Only downside is that all the knobs are the same size & rather closely packed.
Hexinverter Mutant Bassdrum
Killer kick sounds. Mix the distorted and clean signals to taste. Iām sure there may be better kicks out there (& I do scope them out from time to time) but this is super solid.
Honourable mentions - sq-1, hermod (though lately Iām just using it as a fancy midi-cv converter)
I built two small racks, but omg I donāt know 90% of titles here 
Worng Soundstage
Joranalogue Filter 8
IME Piston Honda or Hertz Donut (both are awesome)
Cosmotronic Delta V
Joranalogue Generate 3
Those are the ones that seem most crucial to my rack! Good to see lots of delta v love on this thread.
3x ZOIA Euroburo, 1x Poly Effects Hector, plus a mixer module.
Because I like lots of small multi-coloured buttons and touchscreens.
Top 5 is tough. But I have 5 modules Iām always excited to use.
Intellijel Metropolix: so easy to tweak and dial in awesome riffs. I really love a playable module is this one takes the cake.
Noise Engineering Manis Iteritas: it just sounds nassttttyyy. I love it.
ALM Pamās New Workout: does everything. Menu diving is minimal.
Mannequins Three Sisters: worth the hype. Itās a characterful filter. I wouldnāt pay ridiculous second hand prices for it though.
Acid Rain Navigator: the fader is so simple and deliciously smooth.
Runner up-- Antimatter Audio Brain Seed: a fun little CV recorder. Iāve yet to explore all the possibilities.
Metropolix - the ultimate riff machine, itās hard to get anything bad out of it
Nerdseq+expanders - itās like an m8 except I can patch it. Super deep and can compose whatever you want on it
Akemis Castle - itās huge but I just love loading it with modulation and making crazy drones
Plonk - I love the quirky sounds I can get out of it, always makes me smile
Quaid Megaslope - Really immediate and satisfying modulation source
Teletype - itās an absolute beast. Gotta work it, but the possibilities are endless
Mimeophon - best delay ever
Generate 3 - lovely stuff. Extremely versatile VCO
Pamās - itās in every patch. Essential.
Disting EX - itās menu divey, but what other module supports multi sampling over i2c? What other module is an entire synth engine? What other module can switch to be any other module (or close enough). The screen is a game changer over mk4.
hard to say, as I think its so dependent on what you are doingā¦
Im generally happy with what Ive got, though many act together, rather than being ālone rangersā,
but the following 2 are āstand outsā for meā¦
Percussa SSP
too many reasons to list, but its the way I interface eurorack to the world and my ideas
(go watch my video for more concrete reasons, how I use it etc)
Mutable Instruments Elements - I love Rings, but Elements was why I got into eurorack, and it still exposes such a wonderful range of sounds, both alone and combined.
apart from thatā¦ but not quite same levelā¦
special mention to Xaoc Liebniz (particularly Drezno/Jena) and Qubit Nebulae.
also Bela Salt, but thats pretty specialised, to get the most out of it.
but at the end of the day, I hope/believe my Eurorack is more than the sum of its parts.
I like elements more than rings, Iām with you in how good it is. Sometimes I forget what it can do until I patch it. To be fair, they are actually really quite different but I still prefer the sounds I get from elements.
Maths - Itās just too useful for all kinds of stuff.
Three Sisters - Itās in 90% of my patches. Fun as an oscillator, weird filter, tone shaper, and distortion. Can do surprisingly sharp and precise FM too.
Just Friends - I actually love it without any i2c involved. Playing with intone is nice for chord inspiration and grimy, moody FM.
Sport Modulator - Nice complement to Maths; you can make sequencers and filters and PWM oscs and all kinds of weird stuff with it.
Teletype - The reason I donāt need standalone sequencer modules. Shape shifting CV swiss army knife that pulls me into a real machine mind meld.
Do you have any recommendations for just friends tutorials? I canāt understand the manual at all and last I checked there are barely any videos going in depth on how to actually use the thing. Itās the one module I have that I just canāt wrap my head around or find a decent well explained YouTube video on how to use it. I am not using it with Teletype
I actually really like the manual, even though itās a bit of a tough nut to crack. Without i2c you can ignore most of it. But it is one of those things you have to come back to with a specific idea or feature you want to explore in mind.
If you stay in sound/cycle mode, itās pretty easy to grok as a sort of harmonic oscillator. The key thing to understand about the intone knob is itās a frequency ratio control. By default, when all the way clockwise the N labels tell you the numerator ratio of the outputs (freq * 1, freq * 2, ā¦ freq * 6). When counterclockwise, itās denominator (freq / 1, freq / 2, ā¦ freq / 6). Close to noon you can even get into unison/supersaw territory. Between those are all kinds of chords and wild unnamed harmonic relationships. The other controls are fairly straightforward tone-shaping in that mode.
Beyond that, it does get weird, but thatās part of the beauty of it. It is an extremely deep (feature-wise) module - lots of folks have cases that are basically just JF, TT, and a few utilities.
Have you looked at the technical map?
So my experience with the few Mannequins manuals Iāve looked at is that they are exercises in creative writing. But someone on MW pointed me to the technical maps, which are a small link in the module descriptions on their website, and those are well-written, detailed documents, basically what they should advertise as the manuals. I like my Three Sisters a lot, but I wish the company werenāt quite so hipster-clichĆ©.
Eloquencer is great sequencer and easy to use.
Plaits does a lot and sounds fantastic.
Rossum Morpheus Z Plane filter such infinite options in a filter module.
WMD Performance Mixer- best Eurorack mixer ever
ALM Busy Circuits Akamieās Taiko a killer FM synth voice
Itās really difficult to pick just five modules!
Yeah, when @crevice said āmanualā I assumed they meant the technical map. Those are great and are a large part of the reason I picked up those modules.
Hereās the JF one:
Hard to pick just 5, but if I must, then:
Usta - Amazing flexible sequencer, simple to use quickly, but has great depth.
Mindphaser - It just sounds amazing. Everything I seem to do with it results in a great sound.
Natural Gate - It just sounds incredibly good.
Desmodus Versio - Wonderful sounding creative reverb.
Arbhar - Beautiful design, wonderful sound & lots of fun. Very flexible granular module.