Moltres----fire, spring, some mountians, etc.
Zapdos-----lightning, dark clouds, etc.
Articuno---snow, ice, wind, some mountians, etc.
Mew--------anything that represents origin or mystery (ruins, waterfall, anything that shows cause and effect, etc.)
Mewtwo-----remote locations, anything that can represent duplication (cities with similar looking buildings, anything that looks new, be creative with mewtwo)
Entei------volcanos, smoke, mountians, etc.
Suicine----flowing river, the wind, sparkling water, etc.
Raikou-----lightning, clouds, fast bolts, etc.
Lugia------deep sea trenches, whirlpools, tornadoes, etc.
Ho-oh------the sun, chaotic flames, the sky, etc.
Celebi-----trees, clocks, anything that represents parrallel times
Regirock---earth, mountians, showment of strength, etc.
Regice-----prismatic chunks of ice, caves, showment of skill, etc.
Registeel--odd caves, NO TECHNOLOGY (i know its tempting cus hes a robot, but there is rarely any association of Registeel and other technology) showment of density, etc.
Latios/Latias--representation of direction, wind, minimal land, etc. (best paired togethor)
Groudon----land, lava, mountians, minimal water, the sun, etc.
Kyogre-----the sea, rain, dark clouds, minimal land, etc.
Rayquaza---the ozone layar, representation of dominance/balance, clouds, minimal weather, etc.
Deoxys-----outer space, meteors, the unknown, etc.
Jirachi----stars, desire, things that are often wanted, etc.
Rotom------possesion, electricity, technology, etc.
Azelf------showment of willpower, control, domination over oneself, etc.
Uxie-------showment of knowledge, books, the mind, memories, etc.
Mesprit----all forms of emotion, sadness, anger, happiness, etc.
Heatran----lava, molten metal, blacksmith forge, etc.
Regigigas--showment of power, dominance, relics and anciency
Dialga-----time, clocks, gears, etc.
Palkia-----space, dimension, portals, etc.
Giratina---opposition, everything that makes absolutely no sense but it does at the same time. dimension, time, unbalance, etc.
Shaymin----clarity, plains, feilds, purity, etc.
Manaphy----the sea, peace, pure water, etc.
Phione-----the sea, peace, offspring, etc.
Cresselia--the cresent moon, happiness, light, etc.
Darkrai----nightmares, shadows, the boogyman, etc.
Arceus-----creation, balance, absolute origin, etc.
Thundures/Tornadus--storms, wind, thunder,chaos, etc. (best paired togethor)
Landorus---balance, peace, earth, etc.
Cobalion---justice, strength, weapons*, etc. *(longsword works best)
Virizion---justice, trees, weapons*, etc. *(dual shortswords works best)
Terrakion--justice, land, weapons, etc. *(axes works best)
Victini----flames, stars, success, etc.
Zekrom-----electricity, ideals, half of the yin and yang, etc.**
Reshiram---flame, truth, half of the yin and yang, etc.**
Kyurem-----emptiness, ice, pure energy, etc.**
**if you use black kyurem or white kyurem use a combination of those two that are fused
Meloetta---music, dance, precision of notes, etc.
Genesect---laboratories, team plasma's symbol, upgraded anciency, etc.
Xerneas----life, the forest, peace, etc.
Yveltal----destruction, chaos, the skies, etc.
if i missed any, please let me know, i also might not have done the bestt job, these are what i could come up with to help with that challenge. these are good represented themes for each legendary pokemon.
hopefully this could help -3-