XL900 the original mid compression version
XLH900  same as the standard XL but with the "H" denoting the high compression engine
XLC900 off-road version of the XL,  The XLC has magneto ignition and kickstart only (as well as several other changes to eliminate weight).

XLCH900  off-road version of the XLH - or the XLC with the high compression engine! -
the "CH" denoting "competition/high-compression".
after a year lights, speedo and full road legal specification arrived.

XLX-61 an entry level "Ironhead" era Sportster, available with sparse trim, in black with black exhaust and handlebars or red with chrome exhaust and handlebars.

XLS1000
XLT1000 "Tourer" 1977 special model had a Superglide tank, screen, bigger seat and panniers
XLCH, XLH and XT models of the 1977 Harley-Davidson Confederate Edition that had commemorative paint and tank and fender decals.
Very low volume production of only 45 XLCH, 229 XLH and 15 XT models.

XLCR1000 "Cafe Racer" is the Cafe Racer model, available in 1977 and 1978.

XR1000, two high rise flat track style exhausts on the left and two staggered K&N type filters feeding Dell'Orto carburetors on the right.
Had a 1,000 cc engine and a combination of XLX Sportster and modified XR-750 parts.

XLH883 -
XLH1100
XLH1200
XLH883 "Deluxe", twin seat, tachometer, buckhorn bars, and spoke wheels (vs single seat, speedometer only, low bars and cast wheels for the XLH883 standard model)
XLH883 "Hugger", with reduced single seat height and reduced suspension, the precursor to the "XL low" models
XL53C "Custom 53" (EU) XL883C "Custom" (US) '98–'03 (883 cc or 53.9 cu in), Forward-controls, duelseat, solid rear wheel and drag bars mounted on a riser.
This became the XL883C "Custom" worldwide with the '04 rubbermount version
XL883 "Sportster 883" single seat standard model, mid-controls, 13-spoke mags or wires
XL883C "Custom" has wider, flatter "custom" tank, forward-controls, duelseat and 21-inch wire and 16-inch solid disc wheels
XL1200C "Custom" Frame mount models had a chunkier dual seat and normal tank, rubber mounts get smoother seat and flatter wider "custom" tank, all have 21-inch wire and 16-inch slotted disc wheels and forward-controls
XL883L "Low"; Single seat, very low shocks, mid-controls, 13-spoke mags or wires
XL1200L "Low"; Dualseat, mid shocks, mid-controls, wider flatter "Custom" tank, 13-spoke mags or wires
XL1200S "Sport" – this Sportster has adjustable suspension with piggyback shox, dual disc front brakes, hotter cams and 13-spoke mags, later models get dual plug cylinder heads with single fire ignition
XL883R "Roadster" Frame mount models have a 2–1 exhaust, 13-spoke mags, black engine and are available in orange with 'R' graphics, rubber mounts get 2–2 exhaust, slightly different dualseat, wire wheel option and more 'R' colors, all have triple discs and rev-counter.
In 2010, the XL883R officially gets the "Roadster" suffix
XL1200R "Roadster" Black engine with highlighted fins, triple discs, rev-counter, orange paint available but no 'R' graphics and '08 models get the wider flatter "custom" tank which distance it further from the 883R
XL50 1200 "50th Anniversary" 2007 limited production of 2,000 models
XL1200N "Nightster" first of the Dark Customs, combined LED tail/brake/indicator lights, tapered silencers (EU) and side-mounted LED-lit licence plate, 11-inch shocks, and baloney cut silencers (US), mid-controls and wire wheels
XL883N "Iron 883", blacked-out 883 similar to the Nightster with more black and 13-spoke mags, mid-controls.

XR1200 More sports orientated "Euro"-style bike, male-slider forks, reworked Sportster engine with XR heads, new chassis, four-pot double discs, 120/70-18 and 180/55-17 split 3-spoke mags, rear-controls - has its own race series
XL1200X "Forty-Eight", in the "Dark" Nightster style but has the classic 1948 style small peanut tank, wire wheels, forward controls, a whole new 130 mm front tire, and super small single seat
XR1200X Starting as a XR1200 with piggyback/fully adjustable shocks, fully adjustable front end, available in either Black Denim or White Denim
XL900 the original mid compression version
XLH900  same as the standard XL but with the "H" denoting the high compression engine
XLC900 off-road version of the XL,  The XLC has magneto ignition and kickstart only (as well as several other changes to eliminate weight).
XLCH900  off-road version of the XLH - or the XLC with the high compression engine! - the "CH" denoting "competition/high-compression". after a year lights, speedo and full road legal specification arrived.
XLX-61 an entry level "Ironhead" era Sportster, available with sparse trim, in black with black exhaust and handlebars or red with chrome exhaust and handlebars.
XLS1000
XLT1000 "Tourer" 1977 special model had a Superglide tank, screen, bigger seat and panniers
XLCH, XLH and XT models of the 1977 Harley-Davidson Confederate Edition that had commemorative paint and tank and fender decals. Very low volume production of only 45 XLCH, 229 XLH and 15 XT models.
XLCR1000 "Cafe Racer" is the Cafe Racer model, available in 1977 and 1978.
XR1000, two high rise flat track style exhausts on the left and two staggered K&N type filters feeding Dell'Orto carburetors on the right. Had a 1,000 cc engine and a combination of XLX Sportster and modified XR-750 parts.
XLH883 -
XLH1100
XLH1200
XLH883 "Deluxe", twin seat, tachometer, buckhorn bars, and spoke wheels (vs single seat, speedometer only, low bars and cast wheels for the XLH883 standard model)
XLH883 "Hugger", with reduced single seat height and reduced suspension, the precursor to the "XL low" models
XL53C "Custom 53" (EU) XL883C "Custom" (US) '98–'03 (883 cc or 53.9 cu in), Forward-controls, duelseat, solid rear wheel and drag bars mounted on a riser. This became the XL883C "Custom" worldwide with the '04 rubbermount version
XL883 "Sportster 883" single seat standard model, mid-controls, 13-spoke mags or wires
XL883C "Custom" has wider, flatter "custom" tank, forward-controls, duelseat and 21-inch wire and 16-inch solid disc wheels
XL1200C "Custom" Frame mount models had a chunkier dual seat and normal tank, rubber mounts get smoother seat and flatter wider "custom" tank, all have 21-inch wire and 16-inch slotted disc wheels and forward-controls
XL883L "Low"; Single seat, very low shocks, mid-controls, 13-spoke mags or wires
XL1200L "Low"; Dualseat, mid shocks, mid-controls, wider flatter "Custom" tank, 13-spoke mags or wires
XL1200S "Sport" – this Sportster has adjustable suspension with piggyback shox, dual disc front brakes, hotter cams and 13-spoke mags, later models get dual plug cylinder heads with single fire ignition
XL883R "Roadster" Frame mount models have a 2–1 exhaust, 13-spoke mags, black engine and are available in orange with 'R' graphics, rubber mounts get 2–2 exhaust, slightly different dualseat, wire wheel option and more 'R' colors, all have triple discs and rev-counter. In 2010, the XL883R officially gets the "Roadster" suffix
XL1200R "Roadster" Black engine with highlighted fins, triple discs, rev-counter, orange paint available but no 'R' graphics and '08 models get the wider flatter "custom" tank which distance it further from the 883R
XL50 1200 "50th Anniversary" 2007 limited production of 2,000 models
XL1200N "Nightster" first of the Dark Customs, combined LED tail/brake/indicator lights, tapered silencers (EU) and side-mounted LED-lit licence plate, 11-inch shocks, and baloney cut silencers (US), mid-controls and wire wheels
XL883N "Iron 883", blacked-out 883 similar to the Nightster with more black and 13-spoke mags, mid-controls.
XR1200 More sports orientated "Euro"-style bike, male-slider forks, reworked Sportster engine with XR heads, new chassis, four-pot double discs, 120/70-18 and 180/55-17 split 3-spoke mags, rear-controls - has its own race series
XL1200X "Forty-Eight", in the "Dark" Nightster style but has the classic 1948 style small peanut tank, wire wheels, forward controls, a whole new 130 mm front tire, and super small single seat
XR1200X Starting as a XR1200 with piggyback/fully adjustable shocks, fully adjustable front end, available in either Black Denim or White Denim 
Harley-Davidson Sportster