>>46922492>HMsI'm glad you mentioned that, my featherless friend! firstly, that statement applies to neither the sewers nor the relic passage nor most of lostlorn forest. but even discounting those, there are places you can access right off the bat. I can't be assed to grab more maps, so I'll just list them.
-Chargestone Cave's third floor, where you can find some trainers and items, most notably a thunderstone which you can use on the Tynamo you might catch, because's they're significantly more common on the lowest floor. rewarding exploration with easier access to powerful team members? sounds like good game design to me. (too bad I always use Joltik.)
-the desert resort and relic castle in BW2. gobs of new pokemon and trainers. it's a must-visit, but it's also completely optional.
-hidden grottos all throughout the region. walk right in and grab an item or rare pokemon. you've got to be observant to find them though.
-route 14, again in BW2. you need HMs to reach the abundant shrine, but all of the trainers and wild encounters are yours as soon as you reach undella town.
-the strange house. exclusive encounters and you get the lunar wing. I think the TM for shadow ball is there too.
-shopping mall 9
-reversal mountain has a whole other path that leads to Heatran's den.
god, there is just so much of Unova.