how about ...

• names of WWII fighter planes ( mustang, spitfire, black_widdow, thunderbird, lightning, etc)
• mixed drinks (bloody_mary, pinia_colada, screwdriver, etc)
• euphemisms (can, jon, wank, porcilan_goddess, etc.)
• months (january, february, march, etc.)
• trees (elm, silver_maple, spruce, etc.)
• engine parts (cam, valve, distributer etc.)
• composers (mozart, beethoven, chopin, etc.)
• space shuttles (chalenger, discovery, etc. )
• elements (gold, sulpher, hydrogen, lithium, etc.)
• presidents (washington, lincoln, jefferson, carter, nixon etc.)
• birds of pray (eagle, falcon, hawk, vulture, etc.)
• plains animals (gerbil, antilope, scorpion, buffalo, mormon, etc.)
• board games (monopoly, chess, parchisi, go, othello, stragego, ce, etc.)
• monopoly properties (boardwalk, baltic_ave, indiana, marvin_gardins, reading_r_r, water_works, chance, etc.)
• arachnids (black_widdow, scorpion, lobster, horseshoe_crab, lice, etc.)
• diseases (lice, siph, staph, strep, flu, tendonitis, r_m_s, etc.)
• power tools (drill, sawzall, rotary_hammer, hole_shooter, screwgun, tablesaw, etc.)
• colleges (bates, harvard, northeastern, brandeis, williams, carnege_mellon, rpi, mit, etc.)
• fairy-tale characters (rumplestiltskin, jack, mermaid, snow_white, rose-red, wolf, hunter, grandma, repunzel, baker, evil_witch, good_witch, dorothy, etc.)
• shakespearian characters (henry_V, othello, dromeo, romeo, juliet, hamlet, richardIII(dick3), puck, tatiana, oberon, etc.)
• small fuzzy animals (gerbil, rabbit, cat, rat, buffalo, shrew, etc.) forms of gambling (megabucks, poker, blackjack, driving_a_hyundai, roulette, banko, etc.)
• people who might be dead (elvis, jfk, marilyn, jimmy_hoffa, hitler, eichmann, etc.)
• fast food (macdonalds, wendys, antalope, dennys, etc.)
• movie heros (buckaroo, tarzan, godzilla, indaina_jones, leah, chewbacca, vader, schindler, lone_ranger, john_connor, caligula, rhet, etc.)
• movie villians (see previous list)
• extinct animals (dodo, carrier_pigeon, veloceraptor, t-rex, beatnik, auk, etc.)
• sex toys (see previous list)
• fruits (orange, pear, grape, carson, star_fruit, ugly_fruit, peach, bananananana, coconut, durian, tomato, cucumber, kiwi, pomagranite, etc.)
• names for hell (hell, hades, zanthar, eleasian, sco, styx, lethe, etc.)
• mythical beasts (gryphin, pegasus, unicorn, gargoyle, bigfoot, nessie, cthulhu, virgin, etc.)
• famous excellent women (amilia_earhart, marie_curie, regis, etc.)
• types of underware (longjohns, boxers, bikini_briefs, brasiere, chamois, etc.)
• famous rubber monsters, (mothra, godzilla, giant_robot, rodhan, ghidra, gamera, etc.)
• beers (guinness, bass, harpoon, smuttynose, etc.)
• deadly sins (greed, gluttony, sloth, envy, pride, lust, wrath)
• naming schemes (toxic_waste, lubricants, sexual_fetishes, fruits, hell, excelent_women, rubber_monsters, vilians, mythical_beasts, look at the list we made here.)

good enough?