Tetris Effect: Connected

Avatar progress can be seen from 'Edit --> Avatar' in the Event mode menu.

You will start with one avatar (blue fish) and you need to acquire 100 more avatars in this area so that the total collected shows 101/200. Multiplayer avatar unlocks DO NOT COUNT.

Avatars can be gotten in two ways:

1) Awarded for completing 16 of the challenges in the "My Records" area.

Reaching player level 10, for example, shows that the reward is the Manta avatar. I believe you are given all three versions of the avatar for the challenges that award avatars, making it so you can get a total of 48 avatars from the challenges.

2) Given for playing in the Weekly Ritual, which is accessible for 24 hours starting on Saturdays at 7am EST.

By earning a D rank or higher in any Weekly Ritual event, you are awarded (I believe) a single random avatar. How these avatars are awarded might be completely random but scores/ranks may play a role.

As stated previously, there are three versions of each avatar- blue, orange, and purple, and it feels like these tiers reflect a rarity of common/uncommon/rare in terms of the random reward likeliness. You need 100 different avatars and you will get many, many duplicates along the way.

I initially started by completing Weekly Ritual runs as fast as possible with only a single requirement met (the minimum for a D rank) and got a lot of the blue avatars with considerably fewer orange and purples. After spamming this method for a while, it felt like I was getting duplicates almost all the time. I instead started instead playing for score and with A and S rank runs, I felt like I was getting new avatars more frequently, although I definitely still got a lot of duplicates.

It took me maybe five hours to get my 100th avatar and I had completed 15 of the 16 challenges that give avatars from the "My Records" challenge list (I wasn't yet level 100). If you have a completely random chance for avatars with any D rank in the Weekly Ritual, on a long enough timeline you'll get to 100 for this achievement, but it felt like higher ranks gave me a better chance for the orange/purple avatars so it may be that playing for score (which should get more exp towards levels, anyway) may be best, especially once you get most of the blue avatars.

Hey there :)

As of right now the best way of earning this achievement is by playing the current Event mode.

Eddit: as pointed out by maximoose:

Don’t play all clear. Use either of the other 2 modes.
If using combo, get 3 combo’s and then fail, pile the grid to the top, this will end the current game. Can be finished in around 10 seconds.
If using target set, clear 1 line, then pile the grid to fail. Again, takes around 10 seconds per run instead of waiting for the 60s timer to run out.
Go to effect Games, choose All Clear. Get 1 Clear and then let the time run out.


XXXXXXXXX
OLD SOLUTION
You will receive one avatar every 75s, however it is up to Rng if you get the same one.


Expected grind time should be anywhere between 3 to 5 hours I guess.