JeremysITLab free course on Youtube
Keith Barker's Quizzes on Youtube
Subnetting practice
70+ hours playing with Packet Tracer
JeremysITLab practice exams
Wireshark to look at packet captures
Anki flashcards to remember all those acronyms
r/ccna
CCNA OCG by Wendell Odom (for very specific explanations)
CCNP Encor OCG by Brad Edgeworth
GNS3
Anki flashcards to remember even more acronyms
NetSim for CCNP Encor
ExSim for CCNP Encor
Encor whitepapers