Ideas for zombie world deck additions

[!!! (AQ) Blinkill]

I’m very new to yugioh. I remember having cards in 2002 but never really playing. fast forward to today and I’ve been starting my collection up again. I’ve never played an actual duel besides duel Links so I get the basics. I’ve been researching good decks for beginners and I really like the zombie card art and they seem like a good starting place for me to test the waters of actual IRL dueling. I got three zombie horde structure decks and put together a deck. I was just wondering what kinda additions to add to the extra deck or possibly to the main deck to really give it an extra boost. I have the 3 zombie necro synchro monsters but thought about adding 3 king Ha Des and maybe 2 or 3 plague spreaders. My extra deck just feels kinda sad right now with only three of the same synchro monster. And my main deck is built entirely of cards from the structure deck. Any ideas to give my deck some extra spice would be appreciated.