This is a summary of potentially upcoming features in WARFRAME that were found by searching through game data. Most of the entries are not confirmed and the nature of the upcoming features is purely speculative and only derived from filepaths and names.

- WYRMIUS
A sidescrolling Shoot em’ up minigame
An extensive amount of weapons and upgrades can be found in the files. Examples are “RocketLaser”, “RedSpaceInvaderGun” or “BurstLaser”. Enemies mostly consist of standard units found in the game such as Ospreys or MOAs, but entries such as “HeliosBossTargeterGun” and  “KubrowMiniBossSniper” indicate special fights against bosses and minibosses.

- HARTUK
A “GrineerCombatKnife”. It is possible that this is the internal name of the Sheev.

- ARCHWING WEAPONS
Currently there are only three different ones:
 “Imperator”, a “SpaceMachineGun”
“Imspartacus”, referred to as “SpaceSword”
An unnamed “ArchwingRailgun”

- SABOTAGE MISSIONS
Most likely the mission type from Operation Gate Crash as a regular mission type to be added in the future. Files indicate that initially it will be playable in four different tilesets, these being the Grineer Settlement and Forest and the Corpus Ice Planet and Outpost.

- NEW CORPUS WEAPON
Called "CrpBFG”, listed under “Weapons/Corpus/LongGuns/ “.


-HALLOWEEN STUFF
Apparently set in the Grineer Forest tileset. It involves exterminating Infested and searching for cashes labeled as “InfestedPumpkinCocoon”.
Halloween will also bring new Day of the Dead skins for the following weapons: Akvasto, Amprex, Buzlok, Glaxion, Grinlok, Jat Kittag, Kronen, Marelok, Nukor and Vasto. If these can be bought separately or only in the “"Day Of The Dead Weapon Skin Pack II" is not clear.
A Halloween themed armor has also appeared in the files, it is named “Naberus” and currently only consists of left and right shoulder armor. Interestingly this has replaced the Iliac Should Plates that were previously listed under “Halloween2014Wings”.

-MUSTACHES
As part of the “Movember” event, mustaches will be a new cosmetic accessory that occupies the “Head” slot. Here is the original text explaining the promotion:
"Warframes Supports Movember!"
"Get your Moframes ready, Tenno! We have provided all Tenno worldwide with the first of 5 in-game moustaches to help raise awareness for Men’s Health during Movember! To sport your fancy new Mouth Brow, go to -- Arsenal > Appearance > Attachments > Face section -- to equip.
Want to unlock the other awesome crumb-catching styles? Join us in supporting Men’s Health during Movember by donating to the cause at www.warframe.com/movember.As we reach our community donation goals, more in-game cookie dusters will be unlocked. You can only sport these babies through the month of November -- so support the Mo’s! Happy growing, Tenno! #Moframe!"

The following 5 mustaches will be unlocked by default: "The Gentleman", "The Tusker", "The Magnum", "The Villain" and "The Baron".

The following 5 mustaches will be unlocked in this order by meeting the donation goals:
1. "THE CONNOISSEUR"
2. "THE HANDLEBARS"
3. "THE GRINGO"
4. "THE DALI"
5. "THE MONOPOLY"


-NEW DARVO DEALS
Darvo will probably be offering the following deals in the nearer future:
-Atterax 50% off
-Amprex 50% off
-A bundle containing, in Darvos words: “the Hydroid Warframe, the Nami Skyla blades, Triton Helmet, Para Carrier Sentinel and all it’s fancy parts. Hell, I’ll even throw in credit and affinity boosters, just because. Now that’s money well spent.”

-J-3 GOLEM
This boss is currently actively being worked on, gaining new entries for abilities and weakpoints. The latest ones being "Infested Heart Weakpoint" and abilities such as “J3MindControlAbility” and “Electric Shield”, “NaniteAbility” and “PoisonAbility”.

-FOCUS
The focus system is taking shape. Focus lenses are integrated. There are 5 different types, these being AttackLens, DefenseLens, PowerLens, TacticLens and WardLens.
These lenses are linked to different abilities:
ArmorIncrease, HealReceiveBuff, InstantMaxEnergy, InstantMaxHealth, InstantMaxShield and InstantMaxStamina for the “Guardian” lens.
AlliesOnFire for the “Tactician” lens.
EnergyEfficiency for the “Void” lens.
DamageHealsTeam, EnemyArmorReduction, EnemyShieldReduction, HealthIncreaseLink, InstantReviver, RegenWeakerTeammates and ReviveTeamSentinels for the “Ward” lens.
KillerFocusSource, MeleeBuffGreatSwords, MeleeBuffHammersAndAxes, MeleeBuffSwords, NpcAimReduction, PlayerThreatIncrease, WeaponAimBonusPistol, WeaponAimBonusRifle and WeaponAimBonusShotgun for the “Warrior” Lens.


-NEW EXCALIBUR SKIN AND HELMET
The "OBSIDIAN EXCALIBUR" Skin and Helmet are in the files. They are listed under “PSPlusExcalibur”. I’m assuming this means these will only be available to Playstation players, similar to the Obisdian Skana and Lato skins that are already released.