Just to clarify, do you mean Spark.variable() or just variables in your program? If the former, then what Dave said... if the later there are quite a few more... float, uint8_t, uint16_t, uint32_t, int8_t, int16_t, int32_t, bool, byte, char, #define for constants, long... and some others I'm forgetting at the moment.
For LiquidCrystal support, see my post here: