They are found simply floating, after hitting Winged Clouds, or after pulling bows to unravel parts the scenery, among other methods. They come in different colors and sizes. Small-sized ones are worth one bead, while medium-sized ones are worth five beads, and big-sized ones are worth ten beads. Beads also appear on the goal roulette, along with the Smiley Flowers the player has collected.
Some beads—20 in each level—contain Stamp Patches (or Pencil Patches in Poochy & Yoshi's Woolly World). There is no distinguishing feature about beads containing stamp patches, but once the player has completed the level, previously collected beads with stamp patches will be marked with a small icon on subsequent playthroughs. Stamp patch beads can also be indicated by purchasing the 'See hidden items!' Power Badge, which surrounds the specific bead with a glow.
Players can obtain beads by touching the bead with Yoshi himself, or touching the bead using wool thrown by Yoshi. Some beads are only collectable/visible when the player reaches a certain location on the screen or hits a winged cloud. Beads can also be obtained using Yoshi's tongue after purchasing the 'Grab items with Yoshi's tongue!' power badge or are automatically magnetised to Yoshi with the 'Pull items towards you with magnetic force!' power badge.
Beads can be used to purchase Power Badges for the upcoming/current course that will aid Yoshi in his quest. Costs range from 500 beads to 7500 beads, depending on the Badge's strength. If Yoshi gains hearts even when he is already at full health, they are converted into beads.
The maximum number of beads a player can collect is 999,999. The total no longer appears onscreen if more beads are collected after the limit is reached. Collecting 999,999 beads is not necessary for 100% completion of the game.
In Yoshi Theater, exclusive to Poochy & Yoshi's Woolly World, if a viewer gets a question right, they will receive 500 beads.
Yoshi's Woolly World / Poochy & Yoshi's Woolly World