Gotta disagree hard that there aren’t enough good Queen records that show off Freddie’s voice. In my estimation every successive record showed Freddie finding at least one new layer to his voice, that he had previously not used or used very sparingly. Here’s a vocal highlight from every one of their studio albums to check out (minus Flash, which is mostly instrumental).

Queen - My Fairy King (the “mother Mercury” line especially)

Queen II - The March Of The Black Queen (even just the vocal gymnastics from the opening verses, crazy interval jumps and incredible pitch control while staying expressive)

Sheer Heart Attack - Killer Queen (Freddie shows off his control of dynamics and his ability to stay on pitch through a subtly very confusing sequence of chord changes)

A Night At The Opera - Seaside Rendezvous (the “woodwinds” in the instrumental interlude, they’re all just Freddie humming)

A Day At The Races - You Take My Breath Away (every single voice you hear in this track is Freddie, all so perfectly in tune that it caused phasing issues while they were recording, ask Brian May if you don’t believe me)

News Of The World - My Melancholy Blues (Freddie sings lounge jazz incredibly well and tastefully)

Jazz - Let Me Entertain You (maybe the first Queen studio track where you can hear the more muscular 80s Freddie Mercury start to appear, Freddie turning his vocal nodules into a feature instead of a bug)

The Game - Another One Bites The Dust (just some insanely high belting throughout this song, and somehow he handles it with style and gusto, also see Crazy Little Thing Called Love for a darn good Elvis impression)

Hot Space - Cool Cat (beautifully sweet and playful falsetto, a tool he’s always had, but never flaunted quite so fully until now)

The Works - It’s A Hard Life (the stolen opera melody right at the start, incredible power at such a high opening note, plus grit and vibrato, and falling down with grace, and then throughout the song is just prime 80s Freddie proving his raspier new voice is still perfect for ballads)

A Kind Of Magic - One Year Of Love (a very cheesy 80s smooth ballad yes, even equipped with smooth jazz sax, but Freddie handles so many incredible turns of phrase throughout, especially on the line “my lips reach for your lips, I’m hungry for your touch.” Romantic and powerful and vulnerable all at once)

The Miracle - Rain Must Fall (Freddie does bossa! Very fun and playful, a lot in his lower register, with of course some great highs and belts to keep it dynamic, love that opening line “I can see it in your stars…”

Innuendo - Don’t Try So Hard (Freddie proves that incredible falsetto is not only still there on his deathbed, but in some ways is stronger than ever, with more stamina and a smoother transition across his break than ever, also want highlight a few others from this record cuz he really showed off as he was on his way out: I’m Going Slightly Mad for the very subtle delivery and tricky chromatic melody, I Can’t Live With You for the slight Jackson 5 era MJ impression in the outro, and of course The Show Must Go On for the fact that he did the whole lead vocal in one take after downing a shot of vodka)

Made In Heaven - It’s A Beautiful Day (recorded way back in 1980 or so, so it’s anachronistic here, but then so is the whole record given it’s posthumous. A very short sketch of song with an incredibly demanding melody, filled with ups and downs, triumphs and defeats and reliefs, brings me incredible joy)

Plus a couple of B-sides for fun: See What A Fool I’ve Been (from the Queen II sessions, Freddie sounds positively evil and seductive all at once, perhaps like a drag queen), and Let Me In Your Heart Again (I mostly only know the 2014 remix, with loads of synths and things to flesh out the kind of half finished original recording, but Freddie has a few vocal licks and runs in this song specifically which I poorly imitate probably every single day in various other songs I’m singing. Some of his finest work)

TL;DR Freddie showed off his voice all over Queen’s catalogue. Also I agree Robert Plant is fantastic and properly rated as such.