Some queries about device compatibility on a Mac
Just a side note: all these answers could have been very easily found by just typing them into Google.


The majority of card readers will just work out of the box on OS X. If they don't you either need to install a driver or it just isn't compatible. Big brands like Kingston or Sandisk will work 99% of the time.
If you're using SD cards there really is no difference if you're using it on a DSLR or a Mac. The storage medium itself is what is taken into account when using it. You shouldn't need to install an app for hardware like SD cards.
It should connect out of the box. But this question isn't really related to Apple since it's really dependant of the smartphone your using and what software or drivers the manufacturer provides
To have cross platform read/write support on your pendrive on both OS X and Windows the drive needs to be formatted as FAT32 or NTFS/ExFat.
ExFat is only supported starting from OS X 10.6 (Snow Leopard) and NFTS has no out of the box write compatibility on OS X.