Generally speaking, in order to learn perception from juggling, you'll need to juggle items that are of a weight corresponding to your perception skill. The rule of thumb is to juggle something that is roughly 1/10th of your ranks, rounded down to the closest 5. So, for 210 ranks, you'll want to juggle something that weighs 20 stones while for 60 ranks, you'll want to juggle something that weighs 5 stones. There are some jugglies which fall into more convenient places between those weights, so play around and find out which fits you best, taking into account bonuses and spells.

Additionally, there are a great number of juggling items that have popped up over the years. Here are some others:

One Stone

  jade-colored balls, a set of colorful balls, guppy beanbags invaded by a lone toothy shark,
  detailed glass dragons, small pine dragons, rough oak eggs, etched rosewood eggs
  some detailed ebony eyeballs, luscious tropical fruits, yellow crystal lemons
  etched ebony rosebuds, carved cedar skulls, carved obsidian spheres, detailed cedar stars
  etched glass stars, small obsidian stars, small rosewood stars, detailed rosewood yaks
  etched rosewood yaks

  clay shards, green mosaic tiles

  colorful fabric butterflies

  dried bamboo sticks, worthless contracts, stuffed dragons, a set of multi-colored dragons

  blue glass bottles, miniature leather-bound books, green juggling coconuts
  miniature rounded tin helms, oversized silver kronars, miniature pirate ships
  miniature ivory skulls, red wooden apples, some medium wooden shields
  emblazoned with the symbol of the Order of the Dragon Shield, some glass
  vials marked with the naphtha symbol

  some miniature drunken rangers

  golden crowns

  heavy ironwood dragons

  rough juggling clubs

  some pewter-handled hammers (?)

  juggling scythes