I made some changes to the database today and thought it might be helpful to group all the recognized aloe nothospecies here. These are all the Aloe x hybrids that are accepted by the Catalogue of Life. Source page here:

https://www.catalogueoflife.or...

Several entries created today, including nobilis and spinosissima. Database pages here (all natural hybrids except where indicated)... the most common parents are arborescens (8) and ferox (5).

Aloe x anosyana J.-P.Castillon (Madagascar) = A. helenae × A. divaricata
Anosy Aloe (Aloe x anosyana)

Aloe x buzairiensis Lodé (Socotra) = A. perryi × A. squarrosa
Jabal Buzairi Aloe (Aloe x buzairiensis)

Aloe x caesia Salm-Dyck (SA) = A. arborescens × A. ferox
Aloe (Aloe x caesia)

Aloe x commutata Tod. (SA) = A. grandidentata × A. maculata
Aloe (Aloe x commutata)

Aloe x delaetii Radl (artificial hybrid) = A. ciliaris × A. succotrina
Aloe (Aloe x delaetii)

Aloe x eileeniae Gideon F.Sm. & Figueiredo (SA) = A. africana × A. ferox
Aloe (Aloe x eileeniae)

Aloe x engelbrechtii Gideon F.Sm. & Figueiredo (artificial hybrid) = A. arborescens × A. hardyi
Aloe (Aloe x engelbrechtii)

Aloe x gemmelliae Gideon F.Sm. & Figueiredo (SA) = A. broomii × A. grandidentata
Aloe (Aloe x gemmelliae)

Aloe x hertrichii E.Walther (artificial hybrid) = A. lineata × A. vera
Aloe (Aloe x hertrichii)

Aloe x heteracantha Baker (artificial hybrid) = A. arborescens × A. maculata
Aloe (Aloe x heteracantha)

Aloe x hexapetala Salm-Dyck (South Africa) = A. ferox × A. speciosa
Tilt-Head Aloe (Aloe x hexapetala)

Aloe x hoyeri Radl (artificial hybrid) = A. purpurea × A. serrulata
Aloe (Aloe x hoyeri)

Aloe x imerinensis Bosser (Madagascar) = A. capitata × A. macroclada
Imerina Aloe (Aloe x imerinensis)

Aloe x inopinata Gideon, F.Sm., N.R.Crouch & Oosth. (SA) = A. arborescens × A. chortolirioides
Aloe (Aloe x inopinata)

Aloe x insignis N.E.Br. (artificial hybrid) = A. hexapetala × A. humilis
Aloe (Aloe x insignis)

Aloe x keayi Reynolds (Ghana) = A. buettneri × A. schweinfurthii
Aloe (Aloe x keayi)

Aloe x menachensis (Schweinf.) Blatt. (Yemen)
Menacha Aloe (Aloe x menachensis)

Aloe x nobilis Haw. (artificial hybrid) = A. arborescens × A. perfoliata
Aloe (Aloe x nobilis)

Aloe x panormitana Guillaumin (artificial hybrid) = A. brevifolia x ?
Palermo Aloe (Aloe x panormitana)

Aloe x philippei J.-B.Castillon (Madagascar) = A. acutissima var. fiherenensis × A. viguieri
Aloe (Aloe x philippei)

Aloe x pseudopicta A.Berger (artificial hybrid) = A. saponaria x ?
Aloe (Aloe x pseudopicta)

Aloe x puberula (Schweinf.) A.Berger (Ethiopia) = A. campei × A. trichosantha
Aloe (Aloe x puberula)

Aloe x retiefii Gideon F.Sm. (SA) = A. globuligemma × A. marlothii
Aloe (Aloe x retiefii)

Aloe x riccobonii Borzì (artificial hybrid) = A. arborescens × A. capitata
Aloe (Aloe x riccobonii)

Aloe x runcinata A.Berger (artificial hybrid) = A. ferox × A. maculata
Aloe (Aloe x runcinata)

Aloe x schimperi Tod. (SA) = A. maculata × A. striata
Makbontaalwyn (Aloe x schimperi)

Aloe x selmarii Gideon F.Sm. & Klopper (SA) = A. davyana × A. parvibracteata
Aloe (Aloe x selmarii)

Aloe x spinosissima A.Berger (artificial hybrid) = A. arborescens × A. humilis
Aloe (Aloe x spinosissima)

Aloe x tomlinsonii Marloth (artificial hybrid) = A. ferox × A. hexapetala
Aloe (Aloe x tomlinsonii)

Aloe x ucriae A.Terracc. (artificial hybrid) = A. arborescens × A. pluridens
Aloe (Aloe x ucriae)