Hi! Glad to hear that I am not the only one wondering
From what I see, Energica get a lot of stuff from established automotive suppliers (in the end there are not so many anymore) but apparently are keen on not to use an exact copy of a known design. In the end they stick to what I would call an 'Italian' motorcycle design which I like very much. So the usual suspects
are Ducati & Aprilia.
What I found out so far:
Mirrors: The Energica mirrors are quite sophisticated with their streamlined stems. I have not found others yet that I like better.
I remember having seen quite similar looking ones on a used-part website which were for an older Ducati Monster.
As you pointed out, a bit of a problem is the mounting - the Energica mirrors have a M10 thread (normal thread), the thread for the bar/brake mount is M8 and right-wise thread for right and left-wise for left (at least that is what I remember) which appears quite unusual to me. OEM mirrors often have M8 on the mirror and M10 for the bar mount.
I have found M8R/M8R but not M8R/M8L yet.
Mirror mounts: Has anyone besides me noticed that the colors of the 'front' part of the mirror mount (LH) and brake/mirror mount (RG) do not match? When I first saw that I thougt this to be an manufacturing error or a mess-up by the dealer's workshop. But apparently Brembo does not offer this.
There are (nice but pricey) colored substitutes available by OEMs but there seem to be two different bolt patterns of Brembo stuff and I still have to see if the substitutes I found are really matching.
Indicators: As already posted in my separate thread, the design is a near 1:1 copy of older Triumphs. The mount is also the same as for Triumph and BMW. Be aware that US has 10W indicators, EU has 1,9W. Switching to LED is easier for US as you can simply install resistors if the wattage of the LED is too low.
Connectors are from Molex which apparently are subsupplier for a large number of car&moto manufacturers.
The same connectors you find on (some?) Aprilia and MV Agusta motorcycles, in case you are looking for ready-made adaptors.
Frame: Frame of Ribelle, Ego and SS9 looks like an older Ducati Monster design to me. There are frame plugs available for the two lower openings I think, they are the same as for Yamaha Tenere - refer to R&G parts. BTW, R&G offers (to my knowledge) by far the most accessories for Energicas at least in Europe.
For example they have a protector grille for the heat exchanger of Ribelle and SS9, which I can recommend.
Sliders/Frame protectors: Currently I have non-specific cheap Chinese ones which do not require sawing or drilling to make them fit. I you look for better ones, I found that most probably sliders for the Ducati Multistrada will fit.
Left hand controls: I have seen the same on another bike some time ago but can't remember if it was a Yamaha or Ducati.
The space between LHC and mirror mount is wide enough to allow installation of additional switches e.g. for relocated cruise control buttons.
On the bottom side of the LHC there are 'racks' which allow mounting of stuff. There is a design for a 3D-printed switch housing available to put there.
https://www.thingiverse.com/thing:5526533/filesRight hand controls: Appear very Energica-specific to me.
Edit: Brake levers: The original Brembo are neither ergonomic nor looking good to me. I replaced it with a nice red one by Probrake (German manufacturer). But because it's Brembo stuff you should find alternatives everywhere.