What is the opinion of Reddit about the
Headset Buddy ClearMic That fits Bose QC35 – Noise Cancelling Boom Microphone Compatible with QuietComfort 35 Headphones (CM3504)?

I use the Trust gxt 211 reyno external mic.
But if you want to go the other route, any 3.5 to 2.5 cable with mic (see Amazon link in my previous comment) should work.
I have found this also:
https://www.amazon.com/Headset-Buddy-ClearMic-Bose-QC35/dp/B01LRDZLIE

Regarding the Sony MDR 1000x: Is it possible to connect an external microphone to it, such as this for Bose: https://www.amazon.com/Headset-Buddy-ClearMic-Noise-Cancelling-Microphone/dp/B01LRDZLIE/ref=sr_1_1?ie=UTF8&qid=1494081437&sr=8-1&keywords=qc35+boom

https://www.amazon.com/Headset-Buddy-ClearMic-Bose-QC35/dp/B01LRDZLIE