Li'l Bastard Clock Tampering Kit
At some point during the school year, the Clocks all the clocks were set forward 20 minutes, which was caused by Bart using his Lil Bastard Clock Tampering kit, and as a result the entire school has to remain two extra hours to make up for lost time.
1F19 - The Boy Who Knew Too Much

Li'l Bastard Travel Kit
During his visit to Itchy and Scratchy Land, Bart and Lisa, though mostly Bart like to torment the entertainers in the Itchy and Scratchy suits. Bart happens to have a Li'l Bastard Travel Kid Bum Bag, from which he pulls out a Stink Bomb and sends it into an entertainers suit. As a result Lisa flees but Bart is arrested.
2F01 - Itchy and Scratchy Land

Li'l Bastard General Mischief Kit
Bart turns out to be rather positive about moving to the Movemanterian Compound where he intends to cause some mischief, with his General Mischief kit.
5F23 - The Joy of Sect

Li'l Bastard Brainwashing Kit
Directly after Bart leaves his family to cause some mischief he returns to announce that he loves the Leader as it turns out the Movemantarians have their own Li'l Bastard Kit for Brainwashing.
5F23 - The Joy of Sect