Currently waiting on a tax stamp for a 12.5" build, and started looking at handguard options. In order to keep track of everything I decided to put the list into Excel, sorted by length. Although I'm focused on rails in the 11" to 11.8" range, figured I'd expand the list a little and share with everyone. Hoping this can be something we can expand on over time, and make changes/corrections as needed.

Code:
Manufacturer                 Model                                Type       Length (inches)  Weight (oz)
ALG Defense                  EMR V3 M-LOK 10 Inch                 M-LOK               10.00          8.8
Centurion Arms               C4 Rail System - 10.0                Quad                10.00         11.4
Daniel Defense               LiteRail 10.0 Carbine                Quad                10.00         11.5
Geissele                     10 in Super Modular Rail MKI         Other               10.00         13.0
Knights Armament             URX 4 - 10in                         Keymod              10.00         10.2
LaRue Tactical               LT15-10                              Quad                10.00         16.0
Midwest Industries           SS Gen2 10in                         Other               10.00          8.6
Seekins Precision            SAR Handguard 10                     Quad                10.00         10.3
SLR Rifleworks               10in Intrepid - Keymod               Keymod              10.00         10.8
SLR Rifleworks               10in Intrepid - MLOK                 M-LOK               10.00         11.3
SLR Rifleworks               10in Solo Lite - MLOK                M-LOK               10.00          8.2
SLR Rifleworks               10in Solo Lite - Keymod              Keymod              10.00          7.8
Midwest Industries           SS Series Drop In                    Other               10.10          6.8
EraThr3                      E3H1-10                              M-LOK               10.38          8.2
Black Forge                  BF15 10.5in Modular Rail             Other               10.50         18.0
Bravo Company                BCM KMR 10                           Keymod              10.50          6.3
Midwest Industries           SSK Keymod 10.5                      Keymod              10.50          7.7
Midwest Industries           SSM M-LOK 10.5                       M-LOK               10.50          7.8
Midwest Industries           G3-M10                               M-LOK               10.50          8.4
Midwest Industries           G3-K10                               Keymod              10.50          8.3
Midwest Industries           G3-ML10                              M-LOK               10.50          7.9
Midwest Industries           G3-KL10                              Keymod              10.50          7.8
Fortis                       REV 10                               Keymod              10.75          8.6
Knights Armament             URX 3.1 - 10.75in                    Quad                10.75         11.4
Knights Armament             URX 4 - 10.75in                      Keymod              10.75         10.2
SLR Rifleworks               10.75in Intrepid - MLOK              M-LOK               10.75         11.5
SLR Rifleworks               10.75in Solo MID Keymod              Keymod              10.75         11.5
SLR Rifleworks               11in Solo Lite - Keymod              Keymod              10.93
SLR Rifleworks               11in Solo Lite - MLOK                M-LOK               10.93
Centurion Arms               CMR Free Float Rail - 11             Other               11.00         10.4
CMMG                         Revo Keymod Rail 11 Inch             Keymod              11.00          8.0
LaRue Tactical               LT15-11FL                            Quad                11.00         16.0
Noveske                      NSR 11                               Keymod              11.00          9.4
Ranier Arms                  Evolution Rail - 11.0                Keymod              11.00          9.6
Strike Industries            MegaFins-XL M-LOK 11inch             M-LOK               11.00          9.3
Troy Ind                     VTAC Alpha Rail - 11in               Other               11.00         10.2
Troy Ind                     BattleRail Alpha -11in               Other               11.00          9.3
Troy Ind                     BattleRail Bravo - 11in              Quad                11.00         13.4
JL Billet                    MLA 11.2 M-LOK                       M-LOK               11.20          6.8
Troy Ind                     Troy M-LOK 11.3                      M-LOK               11.30          8.7
Troy Ind                     SDMR Rail 11                         Keymod              11.35         18.8
ALG Defense                  EMR V1 M-LOK 12 Inch                 M-LOK               11.50          7.0
Knights Armament             M5 RAS                               Quad                11.50         14.4
Parallax Tactical            FFSSR Gen 2 11.5in                   Other               11.50
SLR Rifleworks               11.5in Solo Lite - MLOK              M-LOK               11.50
Kinetic Development Group    MREX AR M-LOK - 12in                 M-LOK               11.63          8.5
SureFire                     M82 Rifle Handguard                  Quad                11.82          6.8
2A Armament                  Balios Lite Rail M-LOK               M-LOK               11.87          8.0
2A Armament                  Balios Lite Rail Keymod              Keymod              11.87          8.1
ALG Defense                  EMR V3 M-LOK 12Inch                  M-LOK               12.00          8.8
Centurion Arms               C4 Rail System - 12.0                Quad                12.00         14.1
Daniel Defense               Modular Float Rail 12.0              Other               12.00         14.2
EraThr3                      E3H1-12                              M-LOK               12.00          9.0
LaRue Tactical               LT15-12                              Quad                12.00         16.8
MEGA Arms                    Wedge Lock Rifle Length              M-LOK               12.00         13.1
Midwest Industries           SS Gen2 12in                         Other               12.00          9.3
Midwest Industries           MI 2 Piece Forearm - 12.0 Gen2       Quad                12.00         12.9
Midwest Industries           Lightweight M-LOK Free Float 12      M-LOK               12.00          8.2
Midwest Industries           Lightweight Keymod Free Float 12     Keymod              12.00          8.0
Midwest Industries           SSK Keymod 12                        Keymod              12.00          8.4
Midwest Industries           SSM M-LOK 12                         M-LOK               12.00          8.7
Ranier Arms                  Force Free Float System              Keymod              12.00         10.1
Seekins Precision            MCSR V2 Mod Rail                     Keymod              12.00         13.0
Seekins Precision            SAR Quad Rail - 12                   Quad                12.00         12.3
SLR Rifleworks               12in Solo Keymod                     Keymod              12.00          9.5
Strike Industries            12in MegaFins                        Keymod              12.00         11.5