In my opinion, A&G make too big a fuss over mixed i-stems, which are essentially a broad class of nouns that usually feature a genitive plural in -ium and might feature an accusative plural in -īs, but are otherwise regular third declension nouns.
Here are five of their six morphological classes, along with all the examples they offer. (I’m excluding 71.4 because it’s ridiculous that they’ve placed it there at all):
1. Nouns in (n.) -ēs, (g.) -is.
- acīnacēs, -is (m.) scimitar
- aedēs, -is (f.) temple
- aciēs, -is (f.) point, battle line
- caedēs, -is (f.) slaughter
- cautēs, -is (f.) crag
- clādēs, -is (f.) destruction
- compāgēs, -is (f.) structure
- contāgēs, -is (f.) sense of touch
- famēs, -is (f.) hunger
- fēlēs, -is (f.) cat
- fidēs, -is (f.) faith, trust, loyalty, reputation, etc.
- indolēs, indolis (f.) inborn quality
- lābēs, labis (f.) fall, destruction
- luēs, luis (f.) liquid water
- mēlēs, mēlis (m/f.) marten, badger
- mōlēs, mōlis (f.) mass, bulk
- nūbēs, nūbis (m/f.) cloud
- palumbēs, palumbis (m/f.) dove
- prōlēs, prōlis (f.) shoot, offspring, descendants
- prōpāgēs, prōpāgis (f.) shoot, offspring, descendants
- pūbēs, pūbis (f.) young man
- sēdēs, sēdis (f.) seat, office
- saepēs, saepis (f.) hedge, fence
- sordēs, sordis (f.) filth
- strāges, strāgis (f.) overthrow, destruction
- struēs, struis (f.) pile
- subolēs, subolis (f.) shoot, offspring, descendants
- tābēs, tabis (f.) decline, decay
- torquēs, torquis (f.) necklace
- tudēs, tudis (m.) hammer
- vātēs, vātis (m/f.) prophet
- vehēs, vehis (f.) cart-load (quantity)
- veprēs, vepris (m.) bramble-bush
- verrēs, verris (m.) boar
- vulpēs, vulpis (f.) fox
2. All monosyllable nominatives in -s or -x preceded by a consonant.
- ars, artis (f.) skill, art, technique
- pōns, pontis (m.) bridge
- arx, arcis (f.) fortress
3. On the following monosyllable nominatives in -s or –x preceded by a vowel.
- dōs, dōtis (f.) dowry
- fraus, fraudis (f.) deceit, fraud
- glīs, glīris (m.) dormouse
- līs, lītis (f.) case, quarrel
- mās, māris (m.) male
- mūs, mūris (m/f.) mouse
- nix, nivis (f.) snow
- nox, noctis (f.) night
- strix, strigis (f.) channel, furrow
- vīs, vis (f.) force
4. Polysyllable nominatives in -ns or -rs.
- cliēns, -entis (m.) client, follower
- cohors, -ortis (m.) companion
This does not apply to all present active participles!
5. Patrials (nouns denoting birth, class, abode) in -ās and -īs.
- Arpīnās (Arpīnātēs)… Aprīnātium
- Optimās (Optimātēs)… Optimātium
- Penās (Penātēs)… Penātium
- Quirīs (Quiṝitēs)… Quiritium
The (very much non-)Essential AG: 71-2