I definitely recommend the parallax route for mapping, not just with my tiles, but pretty much any tiles. The default map editor is not very forgiving, limiting you to a 32x32 pixel grid, which makes everything super square. Parallax lets you easily place items wherever you want. You can of course combine the two methods by creating your parallaxed map first in GIMP, Photoshop, or whatever other program you like, and then adding extra details and map elements in the editor afterwards.
And thank you to the folk who beat me to answering the questions
The Mega Pack is the High Fantasy 1, 2, and The Deep packs. These are the older packs at this point, the first ones I made (though the High Fantasy 1 pack was re-made so has newer stuff in it) and thus don't have quite the variety of animations and such per character as the latest pack that will be released relatively soon, Wild Steam. The older packs contain mostly 3 frame animation characters, with some updates for 8 frame animation characters. By default, RPGMaker VX Ace utilizes only 3 frames of animation for when a character walks. This is fine for chibi sprites, but isn't optimal for more realistic sprites, which is why I made 8 frame animation character sprites as well - you need scripts to use them, but there are a few options for those, including some you can find in the FAQ section of my website, www.pioneervalleygames.com
If you want side-view battlers, along with more characters, and a toooon more monsters, the Main Party Packs 1 and 2, and Monster Legacy Bundle have all that stuff. Each Main Party pack contains 12 characters, each character has a bunch of different animation character spritesheets, along with battlers for front and side view battles, faces, and more. Same goes with the monsters in the Monster Legacy Bundle. The Mythos Horror bundle is not Fantasy-themed, it is inspired more by H.P.Lovecraft and the Cthulu Mythos, but the characters and monsters in that all have front and side-view battlers, faces, multiple spritesheets, etc.
But if you really want heavy control over your characters, their appearance, and want better walking animations, running animations, idle animations, and much more, then when the Wild Steam pack comes out that might be worth checking out. It is my first pack in about a year, and is the first pack of my 2nd Generation resources which focus far more on giving you control over the resources, to let you make your own characters and other game elements (for Wild Steam, this also includes letting you make your own steam machines and automatons). You can also read up a bit on that on my website as well if you wish.
Anyways, hope some of this information proves helpful in some way. If you have any other questions, you are always free to send me a PM incase I don't see them in a thread.