As a creative exercise, I created some of my own roles for Forbidden Desert. I tried to make them balanced with each other and with the existing roles. Some are pretty bland, but I think others are pretty interesting and would be fun to play. Let me know your thoughts on my roles or post your own.
Engineer (4 Water)
When you draw a gear card you may immediately play it without discarding it.
You may discard a gear card to play a different card from the discard pile. Remove the played card from the game.
Players on adjacent tiles may give you gear cards for free at any time.
Field Researcher (4 Water)
On your turn, you may Excavate or Pick Up a Part for free.
Storm Chaser (4 Water)
You may take up to 1 plus the storm level actions per turn.
Sand Tiles cannot be placed on your tile or adjacent tiles
Survivalist (5 Water)
You may take up to 5 actions per turn.
Collector (4 Water)
Gain a bonus action per turn for each Flying Machine part you have.
Players on your tile or adjacent tiles may give you Flying Machine parts for free at any time.
Whenever a Flying Machine part is placed on a tile, you may immediately take 1 action.
Spelunker (3 Water)
You may move between any two unblocked excavated tiles, as long as one of them is a tunnel. You may remove any sand present on the tile you move to for free.
These look interesting. We only like the excavator and the one who moves diagonal from the main set - so having more to choose from would be good.
My thoughts (without playing them):
Engineer has a lot of abilities. The first 2 are good enough individually. Having all 3 abilities seems to good. That said, I like all of the abilities.
Field Researcher looks good
Storm Chaser - I didn't get the part about the sand piling up, but then realized that you could chase the storm and stand next to it to keep the sand from piling up - cool idea. I don't like the various number of actions since you have others with more actions than normal. It seems to step on their toes. I would tend to keep the storm chaser as is and change the others.
Survivalist - Flat out extra actions I don't like because it doesn't give the character flavor or a role. What if the survivalist was not affected by Sun Beats Down if they were adjacent to a tunnel - including diagonal. That way the survivalist would hang out around their bunker.
Collector - doesn't feel like collecting. Feels like having. How about can pick up Flying Machine parts for free, and when a part is placed you get a free move towards it?
Spelunker - I really like this one. It seems like it could be broken but I don't think off hand that it is.
How about a Prospector - can peak under the tile they are on for free, or can spend 1 action to peak under an adjacent tile (even if blocked).