Here is a brief breakdown of some of the more famous bubbles in history.
the dutch tulip bubble (1630, first ever recorded)
the south sea bubble (1720)
Japan stock/real estate bubble (1990)
.COM bubble (2002)
USA housing bubble (2008)
Where is the next bubble going to appear. I know the bond market is in a 100 plus bubble and this is where im placing my bets.
The student loan bubble could be a concern as its measured in billions and a large proportion of it is likely to not be paid off for a long time, if ever. There's a subprime auto market for car loans and potentially another subprime mortgage bubble. One key issue with those bubbles could be them all being denominated in us dollars. If the US federal government ever defaulted on its debt and fiat devalued significantly it could multiply a net effect of negative implications these bubbles pose.
Overspending bubbles created from cost overruns on defense programs like lockheed martin's F-35 could pose a danger as could bubbles created by wars in the middle east and anti terrorism measures which cost trillions and may sometimes produce questionable results. Then there are other potential issues like credit card and personal debt bubbles.
In a way, it could be pointless to label bitcoin a "bubble" when major and significant portions of the world economy may be bubblish to relatively higher degrees.