There's value for money and then there's value for money and then there's Halo: The Master Chief Collection, which plays host to 106 maps from Halo: Combat Evolved (playable online on console for the first time), Halo 2 (which now supports Forge Mode), Halo 3 and Halo 4. Most run on the original "native" engine, but some have been upgraded with new textures.
GAF user Mr Enigma has done us the favour of listing them (there are three outstanding entries, at the time of writing). Here is the only appropriate response. And here's a little gallery of shots to accompany the list. The map with the big pyramid structure on it is Ascension.
Update - I'm seeing disagreement online about whether maps for the PC versions of Halo 2 and CE will make the cut. 343's Frank O'Connor has told us that they will. "We've actually added a bunch of maps that were never available on the console versions from the PC versions, so they're in there now." We're seeking clarification, though.
Update 2 - A Microsoft spokesperson has told OXM that all maps from the PC versions of Halo 2 and CE are, indeed, included.
From Halo: Combat Evolved
Battle Creek
Blood Gulch
Boarding Action
Chill Out
Chiron TL-34
Damnation
Danger Canyon (PC)
Death Island (PC)
Derelict
Gephyrophobia (PC)
Hang 'Em High
Ice Fields (PC)
Infinity (PC)
Longest
Prisoner
Rat Race
Sidewinder
Timberland (PC)
Wizard
From Halo 2
Ascension
Backwash
Beaver Creek
Burial Mounds
Coagulation
Colossus
Containment
Desolation
District (PC)
Elongation
Foundation
Gemini
Headlong
Ivory Tower
Lockout
Midship
Relic
Sanctuary
Terminal
Tombstone
Turf
Uplift (PC)
Warlock
Waterworks
Zanzibar
Halo 2 maps remastered using a "native" Xbox One engine
Ascension
Lockout
Zanzibar
???
???
???
From Halo 3
Assembly
Avalanche
Blackout
Boundless
Citadel
Cold Storage
Construct
Epilogue
Epitaph
Foundry
Ghost Town
Guardian
Heretic
High Ground
Isolation
Last Resort
Longshore
Onslaught
Orbital
Pit Stop
Rat's Nest
Sandbox
Sandtrap
Snowbound
Standoff
The Pit
Valhalla
From Halo 4
Abandon
Adrift
Ascent
Complex
Daybreak
Erosion
Exile
Forge Island
Grifball Court
Harvest
Haven
Impact
Landfall
Longbow
Meltdown
Monolith
Outcast
Perdition
Pitfall
Ragnarok
Ravine
Relay
Settler
Shatter
Skyline
Solace
Vertigo
Vortex
Wreckage