If there's one thing that players want with their RPGs, it's options. More options. Players want more ways to make their characters. GMs want more ways to build their worlds (or alternate worlds to play around in). It's a little bit of everything. That's where books like the Arclands Player's Guide come in. It's a resource for both players and GMs that includes information about the world of Hermia, as well as new races, classes, and other options for players. The book is up on Kickstarter now.
From the campaign:
Arclands is a game changing campaign setting for 5th Edition Dungeons and Dragons that features all new magic mechanics, races, classes, items, monsters and an original approach to the world's greatest role-playing game.
Three centuries ago in the world of Hermia the skies poured white fire and after millenia, magic returned. Players in the Arclands world exist on the frontier of a newly re-discovered power and each player character is touched by its essence. To wield this fearsome new energy, known as Fate, and to craft it into bespoke spells and abilities, players must find the mystical spell forges, sites of incredible power where raw magic can be crafted into enchantments for equipment, or into new known spells. The new Arclands Spellforge mechanic allows players the chance to design magic for themselves instead of selecting the same old spells time and time again. Every spell is unique to its owner, allowing each player to tailor their magical arsenal for their adventure. This is the heart of the Arclands world.
The campaign's around 4/5 of the way to its goal with 47 days left to go (so, you have some time to save up your nickels, if you need).