Ok, for your high quality backup camera that fits in between your camera phone and your mirrorless, what are the accessories to get. Hat tip to Brian Smith (his list is a little outdated so make sure his recommendations work for the M6),  Kain Photo for SD card recommendations
- Sony Battery and Charger Kit with NP-BX1 Battery Kit ($55). For $55 this includes and extra battery and charger. There is actually a very nice slim line charger that also works called the Sony ACC-TRDCX Travel DC Charger for $50.
- Sony SDHC UZ Class 10 UHS-1 64GB. These don’t need to be super fast, so 94MBps works. You do need the larger cards so you can shoot 4K with the higher quality XAVC-S format. They are $45 for a 64GB card. If you want to save a little, then know that the Rx100-V and VI use the XAVC-S 4K video codec so they need at least 12.5MBps which is a U3 card with V30 video speed supports. So while you could get a really fast 300MB card, you don’t need, it for instance the SnDisk Extreme Pro 64GB is 95MBps read and 30MBps write which is plenty fast and just $27 from Amazon and the price scales linearly to 128GB which you can get for $48.
- BlackRapid Street Breathe Camera Strap. I use BlackRapid for my main camera, super convenient and the strap just stays out of the way. $40 but useful if you want it out of the way but available.
- Sony PCK-LM15 LCD Protective Cover. To keep the nicks out. $12 of cheap protection. Or us the AFUNTA off-brand one for $7. Note that the RX-100 and the A7RIII all share the same size screen, so the QIBOX 3-pack is not a bad idea for $7.
- Newmowa AGR2 Grip for RX100. For $10, get a little grip to make it easier to hold the camera. works for all models from M1 to M6.
- Sony Underwater Housing for RX100. Wow pretty cool if you are doing underwater shots.
