Trending @Accenture; Notice Period impacts good opportunity

I have attended 2 interview with 2 different companies. In 1 I was able to attend till 2nd interview and another one they are yet to provide the slot for 2nd round. Even am getting calls from good opportunity. But some are asking for proof else atleast they need serving np candidate. And also delaying the process as well. I am planning to drop paper next week. Right now I don't have any offer but based on calls I could feel I can attend good companies and face interviews which may even make me more confident. I know it's a risk but in my current project also I don't feel like working since the moment I decided to move on from this company. There is no appreciation, indirect taunting always wants to pull down even for small mistake and many more happened.I need suggestions/ views is it good to drop resignation and then search for opportunity full fledged. Because of my day to day I couldn't able to attend interview calls as well. I want to completely focus on interview preparation and don't want to leave any good opportunity to be missed because of lack of preparation.. Please pour your suggestions/views it would be helpful for me to groom myself and prepare accordingly the the outcomes.