Your Electric type options are very limited in Crystal because you can't get Mareep. I would say the best option is to go with a Kadabra (or Alakazam if trading is an option) and teaching it Thunderpunch, replacing the Drowzee on your team. Drowzee can also learn Thunderpunch, and just teaching it that is an option, although Drowzee/Hypno is very weak in comparison to Kadabra. Kadabra is an incredibly powerful Pokemon ingame thanks to strong Special Attack and Speed and a wide movepool consisting of the elemental punches (which, just in case you are unaware, can be bought in the Goldenrod Department Store).
For actual Electric types, your best options are either Lanturn or Magneton, as sumwun states.