ditto
All Pokemon in Pokemon sapphire can breed. Except for all legendaries.
You can use a ditto.
You can't
U cant breed Rayquaza because its a legendary Pokemon but u can breed other Pokemon as long its not legendary.
In Pokemon Sapphire, the only egg you get from an NPC is the Wynaut Egg from the old lady in Lavaridge Town. You can get an egg from any Pokemon that can breed, as with any other Pokemon game that has the Day Care that allows you to leave two Pokemon there. You can breed any Pokemon that can breed with Ditto (except for another Ditto), which can be caught in Pokemon FireRed and LeafGreen and traded to Sapphire.
either a Female pichu or a ditto
Have a Ditto and breed with whatever Pokemon you please at the daycare. You can't breed Legendaries. If you don't have a ditto, search which compatible Pokemon is best to breed with the Pokemon you want.
breed deoxys
breed pikachu/raichu
Another Abra of a different Gender or a Ditto.
Trade, Train, Evolve, Breed.
A ditto, if you can get your hands on one.