R (from R to R)
R1 (from R1 to R1)
R2 (from R2-D2 to R2-D2)
R4 (from R4M rocket to R4M rocket)
R_ (from R-39 missile to Rüte)
Ra (from Ra to Razorbill)
Rb (from RB211 to RBX)
Rc (from RC to RCU Records)
Rd (from RDDL to RDRAM)
Re (from Re, Norway to Rezekne)
Rf (from RF connector to RFV)
Rg (from RG to RGBA color space)
Rh (from Rhabditida to Rhyton)
Ri (from Ri to Rizpah)
Rj (from RJ45 to RJ-XX)
Rk (from RK to RKO/Unique Records)
Rl (from RLC circuits to RLM)
Rm (from Rm to RMS Titanic)
Rn (from Rn to RNAse)
Ro (from RO to Rozz Williams)
Rp (from Rp to RPR)
Rq (from RQ-1 Predator to RQ-7 Shadow)
Rr (from RR Lyrae to RRS Discovery)
Rs (from RS232 to Rsync algorithm)
Rt (from RT-11 to RTV)
Ru (from Ru to Ruzyne International Airport)
Rv (from RV Triton to RV Triton)
Rw (from Rwanda to RWTH Aachen)
Rx (from RX to RX)
Ry (from Ry to Ryukyu Robin)
Rz (from RZA to Rzeszow Voivodship)