Not only does Serenata have good taste, but also good predictive abilities, too! Here's the top 10.
Alice X Marisa having more doujins than ReiMari will never cease to amaze me. On the one hand, you have the OG Touhou ship that's been around since the 90s, and on the other you have a small-but-popular pairing that's based on shared traits in character design and some minor interactions back in PC-98. Then Imperishable Night rolls around and gives us some excellent MariAli food, just as Touhou's popularity is exploding and Internet forums are growing increasingly popular for the distribution of memes and fanart. Many doujins are written, much shipping is conducted, and the fandom revels in the wonders of snarky greenhorn witch x kuudere professional magician. The heat dies down a bit, as is wont to happen with every flash-in-a-bottle ship, and then we get Subterranean Animism, another extremely popular Touhou entry that rekindles MariAli right up, especially with that legendary sleepover ending.
Once was a miracle, twice is a pattern, and reading patterns is the one thing Touhou fans excel at. MariAli becomes even bigger, even as IOSYS releases their iconic, memetic song, cementing Alice's fandom portrayal as a Marisa-obsessed nerd, while Marisa is typecast as the cheerful harem lead. As is the case with many, many, Touhou characters, memes overcome reality, and the MariAli train moves at light speeds, fed by some minor interactions in Scarlet Weather Rhapsody. At this point, ReiMari are ahead on Pixiv, particularly as more recent manga have shown us just how much time our two leads spend together and how affectionate they are, but MariAli is still a towering juggernaut that dominates the history of Touhou shipping. And with Cheating Detective Satori finally bringing Alice back into the fray and involving Marisa in her story, who's to say that MariAli won't experience a third grand resurgence? Only time will tell, but you bet I'm excited to find out.
This ship is like the Leicester City of Touhou pairings, and I feel like someone ought to make a YouTube video essay about just how meteoric its rise was. Personally, I prefer ReiAli, both because it's interesting and because the idea of the last link in the triangle being as popular as the other two is immensely compelling. But though I'd argue that it's a bit too late in Touhou's lifetime as a series to have another grand, scene-defining ship, ZUN has surprised us before, and who knows what the future might hold?