Author Emergency anime list
I've had this shower thought earlier.

Everyone will have their lowest point in life - that's almost an absolute certainty. To me, I would shut off my social life and stay inside, do whatever I want, whenever I get stressed (or at least I imagine so).

Then I thought about my watchlist... so many titles... Among those, some are absolute trash but some are lovely as well.

And so I've decided that I will save a few titles in case of such a low point; preparing for a disaster, to say the least, just to keep me going and fill any void I have in my heart in said future. These are some shows which I purposefully avoid to save for a rainy day.

I don't want to rewatch anime. I will never get the same feeling of thrill that I had when I first watched it, so this is the only way for me to feel in a future when I might feel nothing but numbness.

Here's some which I placed in that list.

Not everything here are masterpieces like FMA or Death Note but I don't care. A couple weeks back, I binged A Sister's All You Need expecting a good ecchi show. It was beyond that. I absolutely loved all the character interactions and even felt their desperation during some of their low times. I was inspired to make this list by that one scene where (real spoiler) That scene hits pretty close to home. I felt his pain and become fearful of the future. He had friends to rely on but do I really?

What are your thoughts and opinions? Do you want to have an "emergency anime" list as well? Do you feel like you'll need it? Or maybe you have some suggestions, feel free to drop them here.
I don't have any anime to contribute since I generally have ceased to watch anime, but-

I do have list, however I prefer manga, and when I feel really bad I'd rather read something I know i like (because I tend to be disappointed when it doesn't cater to what I want)

Welp, I'm a sucker for good shoujo and for comedy
Judging by your list I dont think its your style but, I will always recommend watching Major, my fav anime/sport, I at times rewatch the first season as it brings back memories.
A bit out of date anime list, my 10s and 9s are what I consider for rewatching.
From it, my emotional list. If I ever get sick of being dead inside, Ill come to this:

As far as filling the void of silence and boredom, currently I turn to Mahouka Koukou no Rettousei.
It has plenty of climaxes and is generic good anime. Note it is of the OP archetype, climaxes are usually/always resolved rather quickly. Also, one of the reasons I can put this on so often is there are no lows. No dreaded scenes you just cant bear to watch. Its is one of the few I can safely put on and enjoy without worrying that it will distract me. In other words, its my goto bg anime.

Ps. this is my social life. Shutting off my social life down means not talking to fellow weebs for a few days longer than usual.
Shits rarely get to me and I don't think I can watch properly in such condition but, Love Live! has always been my series to belong.
I suppose I would re-watch my favorite Comedies.

To Be Hero
Ninja Slayer
Sora no Otoshimono
Chuunibyou demo Koi ga Shitai!
Anne Happy
Maybe K-On
There's some anime where I started watching and then went, 'this is too good! I can't waste it all now' and then stopped watching to save for later.
- Sketchbook: Full Color's (a perfect slow-paced, healing-type anime)
- Kobayashi-san Chi no Maid Dragon (uplifting slice of life fluffiness)
- Hanasaku Iroha (very life, if you know what I mean... work, drama, romantic tensions, ups and downs...)
- Tsurezure Children
- Sora yori mo Tooi Basho
- Toradora

Some anime just have intrinsically excellent rewatch value.
- Azumanga Daioh: slice of life from an older era... repetition is catchy
- Barakamon: slice of life, comedy, FEELS
- Nichijou: enjoy the sakuga and the absurdity
- Haruhi-chan: silliness
- Naruto / Naruto Shippuuden: fillers are fun. No, I'm not kidding. I've already read the manga, so when I started watching the anime, I mainly watched the fillers first, since that's new content (I was bored okay). There are actually lots of good, fun, self-contained stories in there; perfect for a rainy day! (There are lots of feels trips in there too... I really enjoyed the Curry of Life arc and the Yuukimaru arc.)

Some misc comments:
- No Game No Life: this was a fun self-indulgent one; just nonstop psychological games and strategy & tactics. I enjoyed this for the same reason I enjoyed Death Note, Liar Game, and One Outs.
- K-On! is a classic friendship school life slice of life. I'm strangely attached to the French dub for some reason.
- Nozaki-kun is a fun comedy.
When I'm at the lower points of my life, most of the things that make me happy barely lift my spirits sad LOL.

If I feel myself sinking tho, I would watch various comedy and/or introspective anime/videos and sometimes it keeps me afloat just long enough to land somewhere stable.
Blanking out on the titles rn(it usually just comes to me when I'm about to fall XD), so I'll edit them in later.
If I remember that is
I usually just listen to Jpop and anime/game music.
I read webtoons, webnovels, manga, light novels. Or just what I’m in the mood to.
When I comes to anime, I usually watch dark anime to show that it could be worse.
Or something that can distract me and make me immersed into.
As for genres besides dark ones, rom-com, and... yea. Rom-com is the BEST genre to help you feel better and distract you from the mishap irl. Something that makes you laugh is the best. Definitely.
One Piece has been my emergency anime for years.
Whenever I'm really sick, depressed, bored, etc. I just turn my brain off and turn One Piece on.
Maybe it's because of the nostalgia, but it always makes me feel a little better.
I'm usually the opposite and avoid watching/reading things I'm attached to when I've hit rock bottom, for fear of the sad memories becoming associated with those things, due to my reliance on it when I am, in fact, sad. It's happened with music, so I didn't want to chance it with my other media.

However, if I'm just a little bummed out, and need a little pick-me-up, I tend to go for really comforting/calming things, often pretty heavy on slice-of-life, but not always. A list off the top of my head would include:

Or older stuff that brings me back to my earlier experiences with anime:

And so on. Mostly, just something to remind me of simpler/easier times in my life and make me smile for a bit.
For the lowest point in my life I'd just read Machida-kun no sekai. Maybe Voynich Hotel at second.
I watched episode one of Sewayaki Kitsune no Senko-san the other day and now I have episode two downloaded in my phone, just waiting for a stressful day and only until then will I watch it. It has such the perfect fluff that all my stress evaporated after I watched it. And even beyond the anime there's the manga here so I'm pretty much settled for the foreseeable future.