As seasonal events like Easter and Hallowe'en are taking this new format, that consists of a hub with skilling activities, awarding a specific currency to be spent for rewards, I've compiled a list of past MTX rewards themed around Hallowe'en, and other possible rewards that could be added to Death's Spooky Reward Shop. Let's go!
Squeal of Fortune
- Pumpkin amulet (https://runescape.wiki/w/Pumpkin_amulet)
Treasure Hunter/Solomon's General Store
Gosthly outfits, titles and emote (https://runescape.wiki/w/Ghostweave)
Candy corn rewards, including the County Draynor outfit (https://runescape.wiki/w/Candy_corn)
Spooky Spider outfit, parasol, teleport and Incy pet, rewards from a RuneCoin package (https://runescape.wiki/w/Spooky_spider_outfit)
Walk Like a Zombie cosmetic rewards (https://runescape.wiki/w/Walk_Like_a_Zombie)
Plague Doctor cosmetic rewards (https://runescape.wiki/w/Plague_Doctor)
Events
Invention of Disaster rewards (https://runescape.wiki/w/2016_Hallowe%27en_event)
Dimension of the Damned rewards like the Survival outfit and the RIP axe (https://runescape.wiki/w/Dimension_of_the_Damned)
'Til Death Do Us Part rewards, including Ring of Urns and the Urnbreakable title (https://runescape.wiki/w/2018_Hallowe%27en_event)
Other suggestions
Pumpkin ring, an item to transform the player into a pumpkin
Coffin, a cosmetic cape override (https://oldschool.runescape.wiki/w/Gold_coffin)
Tiny Famine and Tiny Pestilence bobblehead pets
Lenian pet (https://runescape.wiki/w/Lenian)
Guitar cosmetic weapons from Demonic Rock Off (https://runescape.wiki/w/Demonic_Rock_Off), cause Death likes music too (see https://runescape.wiki/w/Adamantite_Damsel).