If by solid you mean every track is enjoyable, there's not really a "weak link" song on the album, and the replay quality is there, then personally what I liked and thought was solid:

Full Albums

• SHINee-1 of 1. I really do think this is the most solid album in 2016. Every track is enjoyable, the variety and diversity in musicality/sound is fantastic, and everything overall is fun to listen to, not to mention the concept was a nice throwback.

Mini-Albums

• Red Velvet-Russian Roulette. Concept and title track are excellent, but some of the B-sides are so fun, personal favorites are Lucky Girl, My Dear, Fool, and the incredible whimsically whacky song that is Bad Dracula. *Wonder Girls-Why So Lonely. Absolutely killed it. It's only three songs long but they're amazing. Why So Lonely is summery reggae vibes, Sweet and Easy lives up to its name, and Beautiful Boy is a bop. The Wonder Girls truly are something else.
• CBX-Hey Mama! Title track+concept are fun. It's solid, but I will admit that perhaps I liked it so much because it did sound a little bit similar to 1 of 1 (seriously, Cherish You and So Amazing sound a little too similar for my tastes). The One and Rhythm After Summer are sweet though.

Solo Albums

• Luna-Free Somebody. WHY DID EVERYONE SLEEP ON THIS ALBUM. Amazingness of the title track aside (I still can't get over Luna belting notes and dancing like it ain't nothing), the B-sides are so incredible, I Wish, Galaxy, My Medicine, everything about this album was on point. I'm sad it didn't sell that well.
• Taeyeon-Why. I know some people only liked Why and didn't like the B-sides, but I think they're solid! Taeyeon's vocals+Hyoyeon's rap+tone in Up and Down really wowed me and it was a good combo for the song's beat, and Night's an unexpected chill unwinding bop.
• Jessica-Wonderland. EDM suits Jessica pretty well. I really think Dancing on the Moon is the best B-side track off a solo album this year. I guess it wasn't completely solid (personally I think Tonight is the weak link), but the rest of the B-sides more than make up for it (Celebrate's a jam).
• Jonghyun-She Is. I don't have much to say except that it's so much fun to listen to in its entirety. It's solid. Jonghyun sounds great. And Moon...is something else, that's all I have to say really.

Some honorable mentions: WINGs, Highlight, Square Two (sans the acoustic Whistle), EX'ACT.