On the Sony Alpha Reddit forum people are discussing what lens they regret selling the most. Here is the list of lenses mentioned. Feel free to add your input in the comment system!

Sony E-Mount Lenses (Native)

• Sony 40mm f/2.5 G : The most frequently mentioned lens. Users regret selling it due to its compact size and “look,” with several people reporting they bought it a second time.
• Sony 90mm f/2.8 G Macro : Mentioned as a lens someone bought back twice after selling.
• Sony FE 24-105mm f/4 G OSS : One user regretted selling it for “peanuts” and eventually bought another copy.
• Sony 70-200mm f/2.8 GM II : A user sold it but bought a used copy back just two months later.
• Sony 50mm f/1.4 GM : A user noted that selling this lens “still makes me cry.”
• Sony 70-350mm G (APS-C) : A user wished they had kept this even after moving to a full-frame A7CR.
• Sony 20mm f/1.8 G : Mentioned as a lens bought back after selling, and another user traded it (along with a 35mm) for a zoom and seemingly missed it.
• Sony 24mm f/1.4 GM : Sold during a system switch and deeply missed.
• Sony 35mm f/1.4 GM : One user included this in their list of most-wanted-back lenses.
• Sony 35mm f/2.8 ZA (Zeiss) : Missed for its “Zeiss punch” and small size.
• Sony 55mm f/1.8 ZA (Zeiss) : Frequently mentioned as a classic lens users love and miss the “look” of.
• Sony 50mm f/1.8 : One user admitted to selling and buying this lens back twice.
• Zeiss Batis 85mm f/1.8 : Described as “magical” and missed after selling.

Lenses from Other Systems (Fuji, Canon, Pentax, etc.)

• Fujifilm XF 56mm f/1.2 : Mentioned by multiple users who switched from Fuji to Sony.
• Fujifilm XF 18-55mm f/2.8-4 : A user realized they shouldn’t have sold it because it was “beautiful.”
• Fujifilm XF 18mm f/2 : One user stated they “look for [this] constantly.”
• Canon 28-70mm f/2.0 L : Highly praised and missed after a system move.
• Canon 85mm f/1.2 L : Mentioned as a regretted sale during a system switch.
• Canon 80-200mm f/2.8 L : Specifically the older “Magic Drainpipe” version.
• Canon TV 50mm f/0.95 : A rare specialty lens mentioned with regret.
• Pentax A* 135mm f/1.8 : Called the “best full-body portrait lens” the user ever had.
• Pentax 28mm f/3.5 & Leica-R cam 3 50mm f2 : Both mentioned as missed vintage glass.
• Voigtländer 25mm f/0.95 (MFT) : Missed for its “magical warm portraits.”
• Voigtländer 50mm f/1.2 : A user missed the focal length after replacing it with a 40mm.
• Voigtländer 65mm f/2 APO-Lanthar : A user noted they “really want that back.”

Third-Party Lenses for Sony

• Sigma 35mm f/1.2 Art : Sold for a Sony GM, but the user missed the specific “3D pop” of the Sigma.
• Sigma 105mm (Macro/Art) : Mentioned with a sad emoji as a lens missed.
• Sigma 14-24mm f/2.8 Art : Replaced with a lighter Sony zoom, but the user missed the “fantastic corner to corner” quality and wider field of view.