What’s the second fire emblem game? 

According to the latest Nintendo Finantial Report (https://nintendoeverything.com/nintendo-million-sellers-april-2019-new-super-mario-bros-u-deluxe-at-3-31-million-yoshi-over-1-million-more/) Yoshi's Crafted World has reached the million, so it gets added to the list.

Ok, I'm updating the list. I'm having trouble finding articles confirming the million sale for older switch titles, can someone tell me if I'm missing some million sellers? Thank you.

I saw the other thread got bumped, so maybe it is time to bump this one. Any idea how many games made it so far? According to the September 30, 2019 report these games sold over 1 million:

Mario Maker 2
Link's Awakening
FE: Three Houses

I'm pretty sure that Pokemon Sword/Shield qualifies now. Not sure what else we have official numbers on yet.

Sword/Shield sold 6+ million in its first week, so it qualifies. The problem is finding articles confirming the million seller status of games that released in 2018 or 2017 and reached the million this year.

You could remove Labo series and just add Labo Variety Kit it's confirmed 1M seller itself.

You forgot these games:

New Super Mario Bros U Deluxe - 4.59M as of 190930
Monster Hunter Generations/XX - 1.22M as of 190207

Do we have an article confirming the date of those two reaching the million?

From the Nintendo March 31, 2019 report, these games (among others) have sold over 1 million:

LABO Toy-Con 1: Variety Kit - 1.09M
Yoshi's Crafted World - 1.11M
Captain Toad Treasure Tracker - 1.18M
New Super Mario Bros U Deluxe - 3.31M
https://www.nintendo.co.jp/ir/pdf/2019/190425_3e.pdf

The real question is if these games count in the 2018 or 2019 list.  I believe your tracking starts on March 9, but Nintendo's report comes out on March 31.  It is probably safe to put LABO, Yoshi, and Captain Toad in 2019, but I would suspect NSMB U hit 1 million before March 9 this year.  On the other hand, this is the earliest official report I know of so far, so maybe it should belong in 2019?  Basically it's your call I guess.

EDIT: I just saw you have Captain Toad in 2018, so you must have found a source before March 9, 2019 for that number.

Ok, as for the last Nintendo Report, Ring Fit Adventure has reached the million, so it gets added to the list. If I've missed any new million seller, please let me know.

Source: https://www.nintendo.co.jp/ir/pdf/2020/200130_3e.pdf

Thanks, added them as well. I do wonder how are many of the big 3rd parties on the Switch doing. Considering that many of them should have had decent legs, maybe ones like Doom are already above the million? That and indies, but those usually announce the million milestone themselves.