New server? So are we talking no kafra blue potions or are we not serious? *plays song: kafra blues*
Any item that has a high drop rate should have its drop rate and npc sell price reduced.
Remember when iro launched transcendence, they made sure the equips had a nerf on the npc selling price. Do something like that.
For the equips and their slotted  variants that drop from mobs that also sell for zeny over 1000.
Example: Stiletto, Gladius, Boots, Full Plate, Gold Ring, Diamond Ring, Huuma Shuriken, Harp, Two-Handed Sword, Manteau, Ring, Undershirt,
Goibne's Helm, Goibne's Armor, Goibne's Spaulders, Goibne's Greaves, etc.
Drop rate of equips should be under 0.10 and have their selling price changed to 1 zeny.
Items that can be sold to npcs in the game for 1000z or more.
Example: Mastela Fruit, Gold, Pearl, Emerald, Topaz, Witherless Rose, Sardonyx, Sapphire, Zircon, Ruby, Ora Ora, Emperium Anvil, Platinum Bullion, Four-Leaf Clover, 1carat Diamond, Darkred Scale Piece, Embryo Creation Guide, 2carat Diamond, Colorful Key, Elemental Potion Creation Guide, 3carat Diamond, Gold Coin Basket, Treasure Box, Wedding Bouquet, Colorful Brooch, Valhala's Flower, Crystal Mirror, Old Crown, Darklord Soulpiece, Tooth Of Jitterbug, Shard of Gigantes, Frozen Rose, Blade Lost in Darkness, Pirate Treasure, Baphomet Doll, Seed of Life, Osiris Doll, Morning Dew of Yggdrasil, Tuxedo, Anvil, Gold Bullion, Blue Potion, Golden Anvil, Silver Bullion, Stone of Sage, Garnet, etc.
The drop rate of these items should be 0.02 or have their price of zeny reduced to 1 zeny.
This will discourage users from using third party programs and slow down the potential of the server having zeny inflation and it's economy being saturated with a buyer's market. When supply exceeds demand.