1970's Mark Spitz Blue Arena swimsuit, still looks great and very usable.

What is your most beloved suit of all?
 

Like i said before, I really like the Arena water polo and Speedo swimsuits that still fit well. I still have those extra snug swim briefs. I'll wear them once in a while, but not for regular swimming. Those water polo briefs and Speedos make great summer underwear too and really tickle when stripping them off.

I'm a bit gender queer, but my favorite suit is Victoria's Secret Knockout Bikini Bottoms, sadly discontinued. Have several of them in various prints and colors. Love the cut and how they flatter my butt, and they do a great job of covering everything in front, yet still show off my tiny package in a nice flat front profile for all to see. Makes it very obvious why I'm wearing women's bikinis. :)

I also prefer my flat-front suits for that minimized look at the beach, brief or T-back thong style. My usual album https://photos.app.goo.gl/24Vqtsx9JwcziuSZA

My favorite was Parr of Arizona's "Z" brief. Unfortunately they're not in business anymore. I still have a couple left from a few years back. The fit is just right for wearing comfortably all day.