Dropper post specific cables are now a thing - MBR
Zoom SPD-801E Bicycle Bike 31.6mm Hydraulic Remote Dropper Seat Post E – Kasen Bikes
Amazon.com : EXA Form 900i 30.9mm Hydraulic Dropper Seatpost 100mm Travel Remote Cable Control Dropper Post for Internal Routing Bike Frame(345mm Total Length)-30.9mm*345mm*100mm : Sports & Outdoors
PINE 27.2 DROPPER POST – PNW Components
How-to DRILL a BIKE for Internally Routed Dropper Posts - Step-by-step, MTB Frame - YouTube
How to Install a Dropper Post | Dropper Post Installation Guide
Dropper Post External Routing | 30.9 Dropper Post Lever | 31.6 Dropper Post Internal - Bicycle Seat Post - Aliexpress
Routing brake and shifter housing and cables | BikeGremlin
How do you internally route a dropper post cable? : r/bikewrench
Lightweight Mountain Bike Dropper Seatpost Adjustable Seat Post Cycle - Walmart.com
Amazon.com : Satori PRO Road Mountain MTB Bike Bicycle Dropper Post Seat Post Remote Internal Inner Cable Routing 31.6 x 485mm Travel 150mm : Sports & Outdoors
Amazon.com : EXA Form 900i 30.9mm Hydraulic Dropper Seatpost 100mm Travel Remote Cable Control Dropper Post for Internal Routing Bike Frame(345mm Total Length)-30.9mm*345mm*100mm : Sports & Outdoors