Two Tier Lists: One for the OSTs (the actual BL list), one for arranged albums (including "OSTs" for remasters/remakes of games e.g. Oath and Celceta) (in the description)

Falcom Bonus/Arrange Albums Tier List (that I've heard in full so far):
In the brackets are which team worked on the arrange album (the in house Sound Team jdk or outsourcers, though the latter usually does the arrange albums)
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Love a fair bit (S: 5/5): Ys 1+2 Eternal/Complete (Sound Team jdk), Ys: Memories of Celceta (Ys 4 arrange, Sound Team jdk)
Love (A+: 4.5/5): Ys 1+2 Chronicles (jdk band), Ys 1+2 PCE (Yonemitsu and co.), Ys 9 Super Ultimate (jdk band)

Like a fair bit (A: 4/5): Ys 3 PCE (Yonemitsu and co.), Zwei 1 2008 (jdk band)
Like somewhat overall (B: 3.5/5) (these are solid arrange albums but jdk band's generally samey rock/orchestral/jazz arrangements with live instruments don't stick with me nearly as much as Sound Team jdk and Yonemitsu's more video-gamey music. I just could not care about the vast majority of the following even if I enjoy listening to it in the moment):
Sky Zanmai (jdk band), Ys Zanmai (jdk band), Sky FC SAV (jdk band), Zero SAV (jdk band), CS1 SAV (jdk band), Ys Origin SAV (jdk band), Zwei 1 SAV (jdk band), Ys: The Oath in Felghana (Ys 3 arrange, jdk band), Ys Oath SAV (jdk band), Field Zanmai (jdk band), Boss Zanmai (jdk band), Adol 35th ann. (jdk band), Azure Evolution (jdk band), Zero Evolution (jdk band), Ys 3 MegaDrive/Genesis (CUBE), Ys 3 x68 (Sound Team jdk)

Not that into (C+: 3/5): Ys 8 Super Ultimate (jdk band), Sky FC Evolution (jdk band), Ys 4 Mask of the Sun (CUBE)
Meh (C-: 2.5/5): Ys 3 SFC/SNES (CUBE), Kuro 1 Super Ultimate (jdk band)
Dislike a fair bit, some of my least favourite VGM (D: 2/5): Sky SC Evolution (jdk band + A-music), Sky the 3rd Evolution (jdk band + A-music)

Falcom Music Plan to listen backlog: Sorcerian Utility+Additional Scenarios, Star Trader, DS6: The Legend of Heroes + Mega Drive ver., Dinosaur, DS7: Lord Monarch+Advanced Lord Monarch, The Legend of Heroes II, Revival Xanadu, Lord Monarch Original, New The Legend of Heroes, Sorcerian Forever, Falcom Classics, VM Japan, Vantage Master Portable, Dinosaur Resurrection, RINNE, Sorcerian Online, The Legend of Xanadu + II, Ys vs Trails in the Sky, the billions of fucking arrange albums (note to self make a seperate list later), any fan/doujin albums
Falcom Music Plan to listen backlog - games I actually want to play edition: Brandish pc98, Popful Mail + Mega CD ver. + SFC ver., Brandish 2, Ys IV: The Dawn of Ys, TLOH3 pc98, Brandish 3, Ys V, TLOH4 pc98, Brandish VT, TLOH3 Playstation, TLOH4 Playstation, Brandish 4, TLOH3 Windows, TLOH4 Windows, TLOH5

Falcom composer tier list:
X: Takahiro Unisuga (my favourite VGM composer/arranger & creative mind of all time in general. lol.)

S: Yukihiro Jindo (outsource/band), Ryo Takeshita, Wataru Ishibashi, Saki Momiyama, Hayato Sonoda
A+: Takahide Murayama/Eichiro Yanagi, Shuntaro Koguchi, Tomokatsu Hagiuda, Yuzo Koshiro (only counting his original Falcom works), Ryo Yonemitsu (outsource/arranger), Masaru Nakajima, Naoki Kaneda, Maiko Hattori

A- (good composers but I'm not as familiar with enough yet as the above; or just not as into): Mieko Ishikawa, Atsushi Shirakawa/Tenmon, Toshiharu Okajima (band), Noriyuki Kamikura (band), Hirokazu Matsumara, Hideya Nagata

B: Masanori Osaki, Natsuno Nakamura (outsource)

C: Mitsuo Singa (outsource/band)

Not familiar enough with at all: Hirofumi Matsuoka (1993-2001), Satoshi Arai (1994-1998), Takahiro Tsunashima (1993-1995) and a few others who did early Falcom stuff

Note: I used to keep track of this in the description of my Falcom game ranking list: https://www.backloggd.com/u/seymourflux/list/falcom-ranking--backlog/, but I'm just gonna migrate it to a full list for the sake of it

Note: I might add a blurb on what I think of each OST, as well as a brief list of favourite songs per OST, at some point.