gr-scan is a program written in C++, and built upon GNU Radio, rtl-sdr, and the OsmoSDR Source Block. It is intended to scan a range of frequencies and print a list of discovered signals. It should work with any device that works with that block, including Realtek RTL2832U devices. This software was developed using a Compro U620F, which uses an E4000 tuner. That product doesn’t seem to be available on the US site, but the Newsky DVB-T Receiver (RTL2832U/E4000 Device) has good reviews.
Start scanning at 100 MHz (-x 100) and end at 105 MHz (-y 105), pausing for 5 seconds on each channel (-p 5):