Heart Moving is my favorite of the ending themes. I think it perfectly invokes the classic magical girl and fairy tale feeling of the first season and it's just such a beautiful and romantic song. Rashiku Ikimasho is number two for me because I just love how upbeat and catchy it is.
YES!!! :love: I wish there was a full version of that one. Maybe there is one but they never released it?
Also i have to post this ending song from Sailor Moon PC game. Its fantastic and its up there with all the best endings from SM. Performed by Usagi, Ami, Rei, Makoto and Minako. I wish it was used in the anime. It would be perfect for the Makaiju part of Sailor Moon R.
This is such a difficult question! I really do love most of the ending themes so I can't pick one favorite, but my top ones include Kaze mo, Rashiku, Watashi-tachi, and Tuxedo Mirage.
My thoughts on all of them:
Heart Moving - This one is truly a classic and it has a very nostalgic sound to it. It may not be one of my "favorites" but it's so iconic, so I truly do appreciate it. It sounds retro and like a romantic fairy tale, has some late 80s/early 90s vibes going on. The visuals are also great because of the simplicity and the shades of green/blue throughout. It looks like a living painting.
Princess Moon - Unfortunately, this is the one ending theme that I don't really like. It just bores me. At least the visuals look cool, the ruffles and ripples in Usagi's/Serenity's dress are so vibrant. The song itself, though, isn't vibrant at all to me.
Otome no Policy - I used to really like this song, but nowadays it sounds a bit too rinky-dinky for my taste. It's still a good song in its simplicity and it has a nice melody, but it doesn't stand out to me anymore. The visuals for the ending sequence bored me -- it's just Usagi running. Nothing to see.
Tuxedo Mirage - This is when Sailor Moon's ending themes really started to stand out. It's interesting because S isn't really a season about the romance aspect of the story, but this is such a romantic, sweet song. It's soft and just screams Sailor Moon to me. S was a very popular season so that might have something to do with it. The visuals are strong and the whole presentation is just very classic. A powerful song.
Watashi-tachi ni Naritakute - I adore this song. I would play it on my flute often, lmao. It feels like a dream to me. A very understated and subtle song for such a colorful season.
Rashiku Ikimashou - Another classic SM song. This one means a lot to me. It's so upbeat and energetic, moreso than Otome no Policy is. The visuals are also very strong, especially seeing the disco lights and the Inners posing in their Super forms. A very youthful and exciting piece.
Kaze mo, Sora mo, Kitto - I'm biased because Sailor Stars was the first season I watched in Japanese, lol. I like both versions. It has a strong late 90s feeling to it. This song is really unique among SM's ending themes -- it contains both sad and nostalgic elements but it's also upbeat and a bit whimsical.
Crystal's ending themes didn't really stand out to me aside from Eternal Eternity. I believe PGSM used ending songs in its special acts but it's been so long, I don't recall any details.
EDIT: The movies also had great ending themes! Moonlight Destiny is cute and I love Morning Moon de Aimashou.
Tuxedo Mirage - This is when Sailor Moon's ending themes really started to stand out. It's interesting because S isn't really a season about the romance aspect of the story, but this is such a romantic, sweet song.
This is one of the reasons I feel like this song would have fit better as the ending theme for the second half of R. Like, keep "Otome no Policy" for the first half of the season, as that song perfectly reflect the sense of determination (particularly in getting Mamoru back) that Usagi feels for the first half of the season, but starting with the episode where Usagi and Mamoru end their breakup and get back together, it would have been thematically perfect for "Otome no Policy" to have been switched out with "Tuxedo Mirage", as that song (like you said) has such a romantic feeling to it that it would have fit perfectly with the romantic themes of the R season, and its regal melody and visuals would have complemented all of the Crystal Tokyo stuff that appeared in the final arc of R.
Kaze mo Sora mo Kitto (Slow version)
I love this version, it feels like a farewell... (I'd wish they made a full version based on this ending )