G-strings is a nice lil tuner
Wetransfer is great for sending large files (up to 2 gigs)
Wi-Fi Manager gives you valuable info about wireless connections within range and is helpful in troubleshooting. When I realized my router was on same channel as neighbors, changing was a big help
Anydo is a great task organizer an syncs well with google calendar in addition to its own free Cal program
360 security does a good job of cleaning junk and malware