I'm looking for a list of places where there are NO NPCs to mess with RNG.
I distinctly remember doing something like this back when SS and HG were released. Good times. By the way, WNPC = Wandering NPC (because I like abbreviations).
Listed are areas without any WNPCs. However, RNGing in locations with WNPCs is manageable simply by selecting a Frame 1 IV spread, mashing X to quickly access the menu screen, and capturing a wild Pokemon in order to discern one’s SSF (Shifted Starting Frame) while accounting for any WNPC advancements during Sweet Scent. WNPCs also move during the initial Season Intro Screen. Try saving your game next to a WNPC in order to quickly confirm if you hit your desired seed as they seem move in the same pattern based on your previous save. It’s somewhat tedious, but it’s very similar to RNGing Eggs on Route 3. Oh, how I miss breeding on Route 34 back in HGSS, but I digress.
Alternatively, there is the Careful Walkthrough Approach. Basically, it’s when you avoid as many WNPCs as possible when travelling through a route in order to complete the main story; using Repels to maneuver around them, saving your progress before attempting to walk by one, etc. If you planned this beforehand, then you have a single shot at an WNPC-free zone when going for targets in places like Abundant Shrine, Moor of Icirrus, or Village Bridge.
Enough talk, onto the list:
Wellspring Cave (1F-B1F)
Rumination Field (For the sake of being thorough)
Relic Castle (1F-B6F)
Lostlorn Forest
Chargestone Cave (B1F)
Celestial Tower (3F-5F)
Twist Mountain (Cave with Exit to Icirrus City)
Route 17
P2 Laboratory
Mistralton Cave (2F-Guidance Chamber)
Dragonspiral Tower Entrance (North of Icirrus City, not the area with the bridge)
Dragonspiral Tower Interior (1F-2F)
Route 9
Route 10 (South of Victory Road; the third area of the Badge Check Gates)
Victory Road (1F1, 1F2, 1F3, 2F2, 5F, 7F)
Victory Road (Exterior)
Trial Chamber
Marvelous Bridge
Giant Chasm (Outside)
Giant Chasm (Outer Cave)
Giant Chasm (Inner Cave; including Kyurem’s Cave)
Challenger’s Cave (1F)
To be honest, I was simply passing by as I routinely do (shameless info leeching), but I’d like to take this opportunity to thank everyone on this thread for posing great questions and providing comprehensive answers which allow interested observers such as yours truly to gain access to a treasure trove of tips, which can be used for future RNG projects. In short, Long Live Smogon!