Reddit reviews USB 3.0 SD Card Reader, Rocketek 2 Slots Memory Card Reader with a Build-in Micro SD Card Cap for SDXC/SDHC/UHS-I SD Cards, TF/Micro SD Cards Reader - Take It as a USB 3.0 Flash Drive
We found 2 Reddit comments about USB 3.0 SD Card Reader, Rocketek 2 Slots Memory Card Reader with a Build-in Micro SD Card Cap for SDXC/SDHC/UHS-I SD Cards, TF/Micro SD Cards Reader - Take It as a USB 3.0 Flash Drive. Here are the top ones, ranked by their Reddit score.
2 Slots - SD/MMC + Micro SD. Support SDXC up to 2TB, SDHC, SD, MMC, RS-MMC, Micro SDXC, Micro SD, Micro SDHC Card and UHS-I Cards.Build-in Card Cap to Use as a USB 3.0 Flash Drive: It allow you store the Micro SD cards inside the memory card reader, and don't need to worry about losing the cards.Plug and play; Hot swapping; USB power (no external power or battery); Supper speed USB 3.0 and backward compatible with 2.0/1.1.Auto detect memory card; Support SDXC up to 2TB, SD V3.0, UHS-I standard, latest Micro SDXC and MMC 4.4.24-month manufacturer's warranty and Free lifetime technical support.
Something like this will solve the one slot issue https://www.amazon.com/Rocketek-Memory-Reader-Writer-slots/dp/B00PBOHAR6/ref=pd_sbs_147_2?_encoding=UTF8&psc=1&refRID=1X1KA1MA84GWC9HY73ZC I have one similar that came with an older smartphone, never used it for the phone but it really does come in handy just having it in a draw. The link is just for reference, you can find them a lot cheaper.
This particular one is here. I'm sure it would be on amazon.com as well, or your local amazon.