Toolbox of goodies. Need something go get it!
Creatures
Flamekin Harbinger - main tutor for elementals. Whatever you need, use it to go and get. However, be aware it goes on the top of the library. Nice combo with Sunbaked Canyon if you need something immediately.
Flickerwisp - Gets rid of any blockers. If you need to redo an elemental's ability in the worst-case scenario. Nice ability but is a glass cannon. Fortunately, 3 power can start chipping away with damage.
Fulminator Mage - Counters Tron. Summon + immediately sack = no land you. Make magic fair again! Also, watch people cry if they are land screwed.
Incandescent Soulstoke - Can give a boost to the other elementals. Also, the second ability can close out games with Omnath, Locus of the Roil, Lightning Skelemental, or Spitebellows.
Lightning Skelemental - The ALL-STAR! That damage will almost always go through. Discarding 2 cards at the beginning of the game is nutz. Combos well with Thunderkin Awakener or Vesperlark to get it.
Omnath, Locus of the Roil- Usually the board is filled and the last bits of damage can go through. The second half is just whipped cream on top. IF the game does go long, card draw and adding counters can help.
Phantasmal Image - Copies anything you need on the field.
Risen Reef - Card draw engine and land filler. REMEMBER if you have not put a land that turn, put it in your hand and then afterward put it on the field.
Shriekmaw - Awesome creature removal! Can add more if creature heavy meta.
Smokebraider - Basically a Bird of Paradise but for elementals and slightly better. 2 mana of any color? Yes, thank you!
Spitebellows - Great against Tarmogoyf when they're large and Primeval Titan. Just a great snipe shot against any creature. Can also be brought back by Thunderkin Awakener or Vesperlark.
Unsettled Mariner - Great against control or any creature hate. REMEMBER "Whenever you or a permanent you control becomes the target..." Completely crushes Valakut, the Molten Pinnacle, or Storm.
Vesperlark - Slightly worse version of Thunderkin Awakener but still a great way to get back from the graveyard.
Voice of Resurgence - Great against any creature hate decks. Creates a body after it dies or leaves the field. Also deters any spells on your turn. Catches most people since almost forgot how to play around with it when it was in standard.
Sideboard
Healer of the Glade - Great against mono-red.
Ingot Chewer - Artifact hate
Tormod's Crypt - Graveyard hate
Wispmare - Enchantment hate
Video inspired
https://www.youtube.com/watch?v=Cfj8yaMyXb8&t=39s&ab_channel=TheCodyHope
https://www.youtube.com/watch?v=9ochKtZS4d8&ab_channel=TheCodyHope
Notes
https://www.reddit.com/r/ModernMagic/comments/d1mxbo/70_win_streak_report_with_elementals_the_best/
https://magic.wizards.com/en/articles/archive/mtgo-standings/modern-league-2019-09-06#lerhose
https://www.youtube.com/watch?v=5VD-Cfn_VPM&ab_channel=TarrasqueMTG