Here is the full list of all 75 Firestone Idle RPG achievements. It takes around 200 hours to unlock all of the achievements on Windows.
Kill the first boss
Kill the boss of the stage 199
Unlock the dragon Vermillion
Reach evolution 5 on any guardian
Activate the Ancient Knowledge
Unlock 5 slots in your battle formation
Use the transmute mechanism 10 times
Do a Prestige
Enlighten guardians 30 times
Complete 1 Monster Mission
Complete 1 Dragon Mission
Complete 1 Naval Mission
Reach rank Lieutenant
Reach rank Conqueror
Unlock the hero Blaze
Unlock the Exotic Merchant
Unlock the Temple of Eternals
Unlock the Map
Complete 177 Firestone Researches
Complete 69 Meteorite Researches
Conduct 77 Alchemy Experiments
Complete 33 Exotic Upgrades
Obtain 15 items of Rare or higher rarity
Obtain 10 items of Epic or higher rarity
Complete 5 times all daily quests
Obtain 5 items of Legendary or higher rarity
Complete 42 daily challenges at battle pass
Reach the 30th milestone at the Battle Pass
Hit 500 times the arcane crystal
Level up your personal tree of life to level 30
Complete 20 times all the available guild expeditions
Awaken your heroes 50 times in total
Complete 20 times all the available missions on the map
Join or create a Guild
Join or create a Fellowship
Use the "prestige" 10 times at the temple of eternals
Play 50 times at the tavern
Enchant 1 ancient artifact
Use the enchant function 5 times on any of your ancient artifacts
Complete 2 times all the weekly quests
Use 50 talent points
Use 100 scrolls of any type
Enchant your gear items 100 times in total
Use 20 seals of power on your gear items
Use 20 seals of power on your jewel items
Defeat 30 players at the arena of kings
Use components to upgrade your war machines 100 times in total
Unlock 7 war machines
Use blueprints to upgrade your war machines 150 times in total
Reach level 10 on 5 war machines
Reach level 20 on 5 war machines
Reach level 30 on 5 war machines
Simulate a fight in the training base
Simulate 10 fights in the training base
Reach mission 23 at the war machines campaign
Reach mission 40 at the war machines campaign
Reach mission 51 at the war machines campaign
Reach mission 58 at the war machines campaign
Complete a mission of normal difficulty in the war machines' campaign
Fight 100 times at the arena of kings
Win 1 fight at arena of kings
Reach luck level 3 at the tavern
Obtain 1 gear or jewel items of mythic or higher rarity
Increase the rarity of 1 ancient artifact to titan
Increase the rarity of 1 ancient artifact to angel
Use 5 primordial elements to craft an ancient artifact
Donate 200000 guild coins to a guild
Donate 50000 guild coins to a guild
Reach luck level 10 at the tavern