There are:
Trading platforms (DAS Trader, LightSpeed, thinkorswim, IB TWS)
Charting tools (TradingView, MultiCharts)
Simulators (TradingSim, DAS Trader w/ Replay, thinkorswim OnDemand)
Backtesters (TradeStation, NinjaTrader, MultiCharts)
Automated Strategy Traders (TradeStation, NinjaTrader)
And: AmiBroker, MetaStock, SierraChart, and countless others...
I listed five categories above but keep in mind some software packages fall into multiple categories. For example, TradingView isn't only charting, you can also trade from it, too, if you connect it to a supported broker. And TradeStation covers all categories except replay/Simulation.
DAS Trader is most popular at BBT. I also use it. I've also used thinkorswim but it does not have direct market access (DMA) and it is also noticeably slower (at least 2 or 3 seconds) behind DAS when I run them side by side.
A lot of traders at BBT have had a lot of success using DAS Trader with InteractiveBrokers or CMEG, so I would say start there unless you have a specific reason to do use something else. (which you may find down the road, but DAS Trader is not a bad place to start)