Nothing listed is in any particular order.

Best:

Apology Tour: As someone who feels the "breakup" was mostly Blitzo's fault and was sick to death of seeing the dogpiling on Stolas, it was pretty satisfying for both Stolas and Verosika to essentially say to Blitzo "having trauma doesn't give you an excuse to be a heartbreaking jackass". And they were completely right.

The song was great, seeing Stolas fire back at Blitzo after Blitzo honestly bullied him throughout parts of Season 1 was fun, and I loved seeing Verosika again. Cristina Vee absolutely nails this role, and I loved her  punk-themed outfit. 

She also told Blitzo what he needs to hear and he finally realizes that if he doesn't want to die alone and unloved, something we've known to be a big fear of his for years, he needs to adjust his behavior. We know that Blitzo feels worthless and he doesn't deserve to be loved, but that doesn't mean people didn't love him, and he needed to realize how badly he's hurt people with his behavior.

I know some people were confused by Tex singing, since "Verosika doesn't pay him enough to care". I've always interpreted that as he's her bodyguard, not her therapist, it's not his place to get involved in her personal issues. Not "Verosika barely pays Tex at all".

Mastermind:

Seeing the rest of the Sins was great, even if Leviathan and Belphegor didn't get any lines. I thought Satan's design was pretty cool.

Stolas losing his powers and status definitely shakes things up, and one of the biggest criticisms of his and Blitzo's relationship was the power imbalance. Now that they're on equal footing, a relationship could work out.\

Mastermind is also one of the best songs in the show, and we get some development for Loonie given she calls Blitzo "dad" repeatedly throughout the episode. She also wraps her tail around Moxxie and Millie.

Sinsmas:

Something fans had predicted for a while was Stolas would become IMP's new secretary. I really hope this is the case because I would love to see Loona out in the field more.

Also really liked the fight against Andrealphus, the return of Gigi and Russ, and setting plot points for Season 3 such as Millie being pregnant, and Octavia hopefully finding out just how evil her mother and uncle are.

Oops and Mammon's Special:

Admittedly, the first half of Season 2 didn't have the best start. The Circus was good, but episodes like Seeing Stars and Western Energy had uneven pacing and tone, and Unhappy Campers is a fucking disaster.

This is when the show really felt like it was getting back on track.

Fizz and Ozzie got their own story arc, both episodes were a good combination of action, comedy, and drama, and we got introduced to Mammon. Fizz also got two of the best songs in the show in my opinion; "Look at This" and "Two Minutes Notice"

Hell's Belles:

I really liked this short. Sallie May is a fan-favorite character, we got more dialogue from her besides memes, and it was nice to get a nice, slice-of-life short of two sisters enjoying a day together. 

Good: 

The Circus:

I liked seeing Stolas' childhood and it definitely explains why he acts the way he does as an adult.

I didn't really care for the scenes of young Stolas and young Blitzo, because by the time that episode aired, I did not care about their relationship at all.

Though it was incredibly satisfying to hear Stolas yell "That...was the sound...of a FUCKING DIVORCE!" as well as see him stand up to Stella, demand she get the fuck out of his home, and firmly tell her they are finally getting divorced.

I know Stella's depictions since this episode have been controversial, but if you've been paying attention and aren't a delusional Stella apologist, you'd have known this was coming. This crazy bitch hired a hitman to kill her husband as a response to cheating, after she domestically abused him. 

Exes and Oohs:

This was another episode that was a good mixture of action and drama, and we got to see Moxxie's backstory, which is incredibly tragic, and Crimson is a pretty memorable villain.

Some of the jokes just didn't stick with me, such as Crimson having a bunch of dildos around his home, and the shot of them bouncing right after Crimson backhands Moxxie and threatens to kill him and Millie completely ruins the serious mood.

I'll talk about Chaz more in the character tier list further down.

Mission Weeabooboo and Mission Chupacabra:

They were pretty good mission shorts, and Emberlynn and Gerardo are memorable targets for having such limited screen time. Emberlynn's human and Sinner forms are both cute, but my god is she obnoxious and cringey. 

Ghostfuckers:

The first third or so was pretty slow, but it really picked up after Rolando started using his powers to mess with Blitzo's mind, making him hallucinate possible ways Millie could've died in previous missions, and we finally get the confirmation of his most traumatic moment; Tilla died in the fire that he unintentionally started. It had been hinted at, but not outright confirmed until now.

I like we got to see the backstory of how Blitzo and Millie met and got the backstory that IMP started as just Blitzo, Moxxie, and Loona before bringing Millie on board.

I thought Rolando was a pretty interesting villain and wish they didn't kill him off. I was kinda hoping to get scenes where he would torment Millie, Moxxie, and Loona the same way he tormented Blitzo.

Ok:

Seeing Stars: This is a pretty boring episode, IMO. The only good things that came from it where the meme of Stolas pathetically throwing a water bottle, the flashback of Blitzo met Loona, and the scene with Loona and Octavia.

Western Energy: The A Plot and B plot really didn't mix well together. I feel Blitzo taking Loona to the vet should've been the B plot for a lower-stakes episode. I at least enjoyed Striker getting more characterization, the introduction of Andrealphus, and Moxxie being able to pull a fast one on Striker.

Full Moon: I liked the fight scene and the song, but the gag of the Cherubs being disgusted by everything went on for too long. I know a lot of people didn't like that this wasn't fully centered on Blitzo and Stolas, but I'm actually glad this was the case. The last thing I wanted at this point was 20-25 minutes of Blitzo and Stolas just talking.

Mission Antarctica: The most forgettable of the shorts. The slurring Penguins got old pretty quickly.

Worst of the entire show:

Unhappy Campers: Like I said earlier, this episode is a fucking disaster! 

* Moxxie feels incredibly out of character. Up until this episode, he was mostly the straight man to the shenanigans going on around him. Here, he's a bratty crybaby who wants everything done his way. And his Moxxine persona was incredibly annoying.

* The camp plot dragged. I feel it would've worked better if Millie didn't find Jimmy acting shady right away and she and Moxxie had do some detective work.

* I'll get into this in the character tier list, but Barbie Wire is pretty unlikable. Her debut made a bad first impression on me. I know I've brought this up a lot, but I absolutely hate people that use their sexuality to manipulate others. Strikes a personal nerve with me.

I know some people may be surprised by a couple of these rankings. I'm basing these off of canon characterizations.

Titles speak for themselves.