Clockwise from left to right: "Flare Scarab", "Air Hummingbird", "Aqua Dolphin", "Grand Mole", "Glow Moss" and "Dark Panther".
Unlike most fusions that require a Fusion Summoning card, a new tactic known as Contact Fusion comes into play, which only needs to have the Fusion Material Monsters on the field. However, monsters Summoned through this effect are only allowed to be on the field until the End Phase of the turn of on which it was Summoned. This can be bypassed through the Field Spell Card, "Neo Space", which allows the Fusion Monsters to stay on the field as long as "Neo Space" does, and the Equip Spell "Instant Neo Space", which allows the Fusion Monster it's equipped to to stay on the field. The monster card "G.B. Hunter" can also prevent the final effect of the "Neos" fusions from happening, but will also stop further Contact Fusions. The monsters in this archetype are also bolstered by many support cards that range from swarming the field with "Cocoon Party" and "Contact" to upgrading them with "NEX".
A good card to include is "Elemental HERO Prisma". It can send a "Neos" monster to your Graveyard and have its own name treated as "Elemental HERO Neos". You can then use it for the Summon of a "Neo-Spacian Fusion", or use cards like "Wrath of Neos" on it. You can then use cards like "Birthright" and "O - Oversoul" to Special Summon "Elemental HERO Neos" from your Graveyard. Note that "Neo-Spacians" have low ATK, so a Contact Fusion must be quick.
"Miracle Contact" is also useful, as it can access your hand, your side of the field, or your Graveyard for the monsters you need to Special Summon your "Neos" Fusion Monsters (however, any monster Summoned by "Miracle Contact" cannot be Special Summoned again through other cards or effects). "Contact Out" is especially useful in avoiding card effects that force your monsters to leave the field (such as those of your own "Neos" monsters), or can allow for multiple attacks if your opponent controls 1 or no monsters.
"Elemental HERO Neos Alius" is a Gemini monster whose effect allows him to be treated as if his name was "Elemental HERO Neos." This is very useful in a "Neo-Spacian" Deck, as it gives you the option of having more than three "Neos" to use in Contact Fusion. It is also a Level 4 monster with 1900 ATK. "Neos Alius" can also be used with cards like "Instant Neo Space" in order to Summon the real "Neos" without Tribute. Given that "Neos Alius" is a Gemini monster, he can be supported by cards like "Phoenix Gearfried" and "Gemini Soldier". One popular strategy is to stick exclusively to the most useful "Neo-Spacians": "Dark Panther", "Grand Mole" and "Flare Scarab".
Neo-Spacian Draw Engine
While the original purpose of the "Neo-Spacians" is to Contact Fusion with "Neos", with cards like "Convert Contact", "Cross Porter" and "Space Gift", they've become an interesting Draw Engine, Deck Thinner and Graveyard Filler disregarding "Neos".
"Convert Contact" is the key card, thinning your Deck by 3 cards and sending two monsters to the Graveyard (one of your choice) without making you lose hand advantage. The other key card, "Cross Porter" can be used to keep hand advantage, as it can be easily sent to the Graveyard with cards like "Armageddon Knight", "Foolish Burial", "Dark World Dealings" or "Neo-Spacian Aqua Dolphin". If revived (even with cards like Junk Synchron), it can provide an extra Neo-Spacian.
Once in the Graveyard, these monsters can then be used for different purposes, like the Special Summon of "Dark Simorgh"/"Chaos Sorcerer" or using cards like "The Beginning of the End". Since both "Cross Porter" and "Armageddon Knight" are low-level DARK Warrior monsters, and there is one DARK Neo Spacian and one Warrior Neo Spacian, cards that support DARK monsters (like "Dark Eruption"/"Allure of Darkness") and Warrior monsters (like "Reinforcement of the Army") work quite well.
The first known competitive Deck to use this Engine was Junk and Debris Deck.
The main weakness of the "Neo-Spacians" is that their Fusion Monsters return to the Extra Deck during the End Phase of the turn. Relying on Field and Equip Cards to keep monsters on the field can be easily thwarted with cards such as "Dust Tornado" and "Mystical Space Typhoon". Also, Neo-Spacians are fairly weak on their own, with no specific support cards. Their Chrysalis forms have plenty of methods for Special Summoning Neo-Spacians, but if you dead draw, with no way to Summon Neos, your opponent can lay into you right off the bat.
Neo-Spacian Draw Engine
The main weakness of this Deck is how much it depends on the Graveyard. Cards that banish monsters can completely shut this Deck down.