Three innovative repetitive and multi-barrel deuterium ice pellet injectors have been designed for plasma investigations in fusion facilities. The pellet injector for JET has capability to inject small pellets (variable volumes within 1-2 mm3) at frequency up to 67Hz and velocities 80-200m/s for ELM (edge localised modes) control and large pellets (volume within 35-70mm3) at frequency up to 15Hz and velocities 100-300m/s for plasma fueling. A new extrusion nozzle has been designed and tested to improve the extrusion stability and injection reliability. The pellet injector for HL-2A has a piston type extruder with a variable cross-section. It allows pushing out deuterium ice rod from the extruder at velocity up to 100m/s and injecting a limited number of pellets 1.3mm diameter and variable length in the range 1.3-1.7mm at frequency up to 30Hz for plasma fueling. The pellet injector for fueling of a facility with theta pinch plasma is capable to inject one pellet with variable length from 5 to 15mm and diameter 1 mm with extremely low velocity of about 40-50m/s, followed by eleven pellets with variable length from 1 to 3mm and diameter 0.9mm at velocities 100-200m/s. A novel gas valve with in-built punch mechanism has been developed to simplify the injector design.